Package: pycrate
What is pycratePycrate is a french word for qualifying bad wine (when it's close to vinegar !).
The present software library has nothing to do with wine (except it is developed in France),
it is simply a Python library for manipulating various digital formats in an easy way,
with a funny name. Most of the format supported are related in one way or another
to cellular network's signalling.
It is the glorious successor oflibmich,
which was started back in 2009, served well and retired in 2017.It provides basically a runtime for encoding and decoding data structures, including
CSN.1 and ASN.1. Additionally, it features a 3G and LTE mobile core network.LicenseThe whole library is licensed under LGPL v2.1 and is compatible with more recent
version of the LGPL: all licensed files have an header making it self-explanatory.
For more details, please report to thelicense.txtfile.WikiPycrate has a growingwiki.
Use it as much as possible before opening an issue.
Feel free also to propose some additional content.InstallationOperating systems and Python versionThe library is designed to work with Python 3 (3.5 and greater), from the official Python
implementationCPython, and is systematically tested both on
Linux, MacOS and Windows. It should also support alternative Python engines such aspypy,nuitkaorCython;
this is however not regularly tested. It should also support any other operating systems which
has a decent Python 3 support.Python2 support is entirely abandonned end of 2022, and hence release 0.5.5 is the last one with
full support of Python 2.7.DependenciesCurrently none. Only the Python builtins and few internal modules of Python
(e.g. os, system, re, struct, datetime) are required for most of the features.
The json internal module is required for supporting the JSON API.
If you want to run pycrate in Python2 (which is bad !), you will however need to
install theenum34package.Thepycrate_ether/SCTPmodule can optionally use the externalcrc32cmodule from ICRAR.Thepycrate_mobile/TS24301_EMMandpycrate_mobile/TS24501_FGMMmodules useCryptoMobileas optional dependency to
encrypt and decrypt LTE and 5G NAS messages.Thepycrate_corenetpart requires alsopysctpandCryptoMobileto run.Thepycrate_diameter/parse_iana_diameter_xml.pyfile useslxmlto translate xml files from IANA to Python
dictionnaries ; this is however not required for standard runtime.Thepycrate_osmo/SEDebugMux.pymodule relies on thecrcmodto compute custom CRC in the frame format.Automatic installationAn installation script is available.
As soon as you have cloned or downloaded the repository, you can use it to install
the library within your Python package directory:python setup.py installRun it as superuser for a system-wide install, or as-is for a user home-directory
level install. You can also rundevelopinstead ofinstallif you want a
developer-friendly installation.It is also possible to test the library before installing it
(this will create two local directories./test_asn/and./pycrate.egg-info/that
you can just delete afterwards):python -m unittest test.test_pycrateOr to build the library without installing it in the system:python setup.py buildIt is also possible to recompile all ASN.1 modules, this will take few minutes
(but if I did not do any mistake, all ASN.1 modules provided in./pycrate_asn1dir/should have been compiled with the latest version of the compiler):python -m pycrate_asn1c.asnprocMore generally, installation is not required, and simply having allpycrate_*subdirectories into the PYTHONPATH enables to use the entire library.Installation with pipAlternatively, you can install the library with thepipcommand:pip install pycrateThe install package is available onpypi.
It contains the library from the last tagged release on github (which may be months old).ContributingContact and supportThis library is free software, and you are free to use it (or not to use it).
In case you encounter a problem with it, first read this README completely and then
check theWiki; moreover many classes,
methods and functions are documented with docstrings, and finally you can have a look
at the source code (it won't bite you).If after all those steps, you still have a question or you think you found a bug,
please open an issue (see below). Specific support requires time and may not be always
possible. In case you require such support, please consider also contributing in one
way or another (see below, too).In case you are using this library in any of your project and you find it useful,
do not hesitate to send me an email. It is always a pleasure to know where code provided
on the Internet can end up... (I am personally aware of some dark places where a pycrate's
fork lies).Filling an issueWhen filling an issue, please provide precise and contextual information about
your case and the error you potentially encounter:indicate the version (or commit-level) of pycrate you are using, together with the version of Python.provide a code snippet that leads to the error you are facing, so that it can be reproduced.provide the eventual stacktrace you are getting from Pythonprovide additional and contextual information as needed (e.g. a specific ASN.1 specification being used...)This is the bare minimum if you want to get help.
And when you consider your issue has been addressed, please close it: "A good issue is a closed one !"
as would have said my great grandmother.Extending the libraryIf you are willing to extend the library, do not hesitate to contact me by
email or preferably through the github service (ideally, open a pull request).
For important changes, please elaborate about your need and provide some justification.
Any patch or submission is always very welcome!Other contributionsIn case you do not want to deep dive in the code, you can still contribute in many ways:highlighting specific issues in the inner-working of the library,
and opening an issue with concrete debugging informationwriting new test cases for more coverage (have a look at thetest/directory)sending captures / real-world data that can be used for writing new test caseswriting new parts of the wiki (have a look at thepycrate wiki)Getting contributions is extremely important to encourage the continuous development
of the library, and to confirm the choice made to open-source it.ComponentsPycrate is actually more a software suite than a single library. It is composed
of several subdirectories, each providing specific services.pycrate_coreThe core of the library.utilsprovides basics functions to manipulate integers, bytes and bitscharpyprovides the Charpy class to handle easily the consumption of a bit-streameltandbaseare providing several classes to help when building complex
data structuresreprprovides simple functions to help with the representation of instances
from theeltandbasemodulesSome of the most useful features are provided by thepack_val()functions from
theutilsmodule and theCharpyclass from thecharpymodule.
They help to deal easily with packing and unpacking bytes and integers
(signed / unsigned, little / big endian) in an aligned and unaligned way.
All lengths of fields are provided in bits, hence facilitating the handling of
unaligned structures.pycrate_etherThe modules provided here implement Ethernet and IP-oriented protocols and formats.MPLSwith structures for MPLS label and headerEthernetwith structures for Ethernet and VLAN headersARPsimply providing the structure for ARPIPwith structures for IPv4, IPv6, ICMP, UDP and TCPSCTPwith structures for SCTP headers and various chunksPCAPwith structures for the PCAP global header and the record headerpycrate_mediaThe modules here implement various multimedia formats.JPEGwith detailed structures used in the JPEG formatGIFwith detailed structures used in the GIF formatTIFFwith detailed structures used in the TIFF formatBMPwith structures used in the BMP formatPNGwith the basic structure used in the PNG formatMPEG4with the basic structure used in the MPEG4 file formatMP3with detailed structures used in the MP3 format, including ID3v1 and ID3v2 tagsMost of the classes here implement a complete recipe to parse all of those format in a
single shot, by using theirfrom_char()method.pycrate_asn1cAll the modules here serve the sole purpose of compiling ASN.1 specifications.
The most important ones are:asnobjwhich is the almighty class when parsing any ASN.1 definitiongeneratorwhich provides two distinct generators to produce source files from
the ASN.1 objects processed in Python:PycrateGeneratorwhich produces source
file to be used with the pycrate ASN.1 runtime (inpycrate_asn1rt),
andJSONDepGraphGeneratorwhich produces json file listing object dependencies
(which then can be browsed dynamically thanks to D3).asnprocwhich is the top-level module for the compiler, it contains for example
thecompile_text()function which compiles a serie of ASN.1 modules into
Python objectsThis compiler support most of the ASN.1 language features, including parameterization and
class objects and sets (especially useful when working with table constraints).
It has however few restrictions, the biggest being the need for the left part of the ASN.1
assignment::=being on a single line. Also, old-school ASN.1 macros are not supported ;
hence, the compiler cannot parse SNMP MIBs.pycrate_asn1dirThis subdirectory contains several ASN.1 specifications that are supported and
precompiled for pycrate. Very few specifications have been changed in order to
work with pycrate :Q.775, in which the terribleAllPackagesASis commented outQ.773 and Q.775, in which theTCInvokeIdSetconstraint is modified to be
used as a set of values
That's all !pycrate_asn1rtThis subdirectory contains the ASN.1 runtime, that is loaded and used by the ASN.1
specifications compiled with the compiler inpycrate_asn1c. It supports
the PER encoding rules (aligned and not, canonical also), and the BER, CER, DER
and JER encoding rules.pycrate_csn1This subdirectory contains a CSN.1 to Python translater in the filetrans.py,
and a CSN.1 runtime in the filecsnobj.py, in order to encode and decode CSN.1
structures translated to Python objects.pycrate_csn1dirThis subdirectory contains CSN.1 structures extracted from 3GPP specifications
(in the .csn files), and translated into Python objects. The following specifications
have been used: TS 44.018, TS 44.060 and TS 24.008.pycrate_mobileThis subdirectory implements most of the 3GPP NAS protocol formats:GSMTAP: gsmtap header formatMCC_MNC: dictionnaries for MCC and MNC look-upNAS: provides two functions to parse any uplink and downlink mobile NAS messagesNASLTE: provides two functions to parse LTE uplink and downlink NAS messagesNAS5G: provides one function to parse 5G uplink and downlink mobile NAS messagesPPP: structures for NCP and LCP protocols used for PPP connection estabishment,
as defined in RFC 1661, 1332 and 1334SCCP: structures for SCCP user-data and management messages as defined in ITU-T Q.713ISUP: structures for ISUP messages as defined in ITU-T Q.763SIGTRAN: generic structures for SIGTRAN (i.e. M2UA, M2PA, MTP3 and M3UA) messagesM3UA: structures dedicated to the M3UA format from RFC 4666TS102225: structures for SIM card's Secured Packets from ETSI TS 102.225TS23038: structures and routines for SMS encoding from TS 23.038TS23040_SMS: structures for the SMS transport protocol from TS 23.040TS23041_CBS: structures for the Cell Broadcast Service protocol from TS 23.041TS24007: basic structures from the TS 24.007 specification, reused in most of the NAS protocolsTS24008_CC: structures for call control messages from TS 24.008TS24008_GMM: structures for GPRS mobility management messages from TS 24.008TS24008_IE: structures for many information elements from TS 24.008TS24008_MM: structures for mobility management messages from TS 24.008TS24008_SM: structures for GPRS session management messages from TS 24.008TS24011_PPSMS: structures for the SMS point-to-point protocol from TS 24.011TS24080_SS: structures for the Supplementary Services protocol from TS 24.080,
wrapping some MAP ASN.1 objectsTS24301_EMM: structures for the EPS mobility management messages from TS 24.301TS24301_ESM: structures for the EPS session management messages from TS 24.301TS24301_IE: structures for many information elements from TS 24.301TS24501_FGMM: structures for the 5G mobility management messages from TS 24.501TS24501_FGSM: structures for the 5G session management messages from TS 24.501TS24501_IE: structures for many information elements from TS 24.501TS24501_UEPOL,TS24526_UEPOLandTS24588_UEPOL: structures for the 5G UE policy protocol
from TS 24.501, 526 and 588TS29002_MAPAppCtx: functions that relies on the Pycrate_TCAP_MAPv2v3 ASN.1 module,
dealing mostly with MAP application-contextsTS29002_MAPIE: structure for the MAP AddressString object from TS 29.002TS29244_PFCP: structure for PFCP messages from TS 29.244TS0960_GTPv0: structures for 2G GTP version 0 from TS 09.60TS29060_GTP: structures for 2G/3G GTP-C version 1 from TS 29.060TS29274_GTPC: structures for 4G GTP-C version 2 from TS 29.274TS29281_GTPU: structures for 2G/3G/4G/5G GTP-U from TS 29.281TS31111_SAT: basic structures and dict for the SIM application toolkit from TS 31.111TS31115: structures for SIM card's Secured Packets over SMS from TS 31.115TS38415_PDUSess: structure used in 5G user-place traffic (i.e. GTP-U) from TS 38.415TS44018_GTTP: structure for the single GSM GTTP message from TS 44.018TS44018_IE: structures for many information elements from TS 44.018TS44018_RR: structures for the GSM and GPRS radio ressources messages from TS 44.018TS48058_Abis: few IE structures for the GSM Abis protocol from TS 48.058pycrate_diameterThis subdirectory contains the following modules:parse_iana_diameter_xml: to translate XML Diameter structures from IANA to Pythoniana_diameter_dicts.py: that is automatically created by the former, containing Diameter Python dictsDiameter: a generic Diameter module which implements DiameterGeneric and AVPGeneric structuresDiameterIETF: a Diameter module which relies on AVP types provided in all IETF RFCDiameter3GPP: a Diameter module which relies on AVP types provided in all 3GPP TSpycrate_osmoThis subdirectory contains the following modules:L1CTL: structures to control the osmocom-bb GSM embedded stack from the hostSEDebugMux: structure used by Sony-Ericsson SoC and basebands to wrap logsRRCTL: structures to interact with the RRC layer of the UE emulator from thisforkof srs-ltepycrate_corenetThis subdirectory implements a signaling server that supports IuCS and IuPS over Iuh interfaces
(including HNBAP and RUA/RANAP) for interfacing with 3G femtocells, and S1 interfaces
(including S1AP) for interfacing with LTE eNodeBs.
It handles many procedures to drive femtocells, eNodeBs and mobile terminals connecting
through them. In terms of services, it mostly support short messages and data connectivity.
It does not handle call services, neither active mobility procedures (handovers).It can be easily (common, running a mobile core network is notthateasy)
configured and used thanks to thecorenetproject,
also open-source.pycrate_gmr1This subdirectory contains the main module for the GMR-1 Radio Resources protocol:TS101376_04_08,
and the submodule for specific Information Elements:TS101376_04_08_IE.
This is a partial implementation of the ETSI specification TS 101 376-04-08 for the
GEO-Mobile Radio Interface Specifications (Release 3).pycrate_gmr1_csn1This subdirectory contains all the CSN.1 definitions for the GMR-1 Radio Resources protocol,
extracted from the 3 ETSI specifications for GEO-Mobile Radio release 3:
TS 101 376-04-08, TS 101 376-04-12 and 101 376-04-13.UsageMost of the modules have doc strings. I try also to write readable sources and to
comment them as much as possible for understanding them easily (and to allow also
myself to understand my own code years after...).
Awikiis provided
and extended from time to time, to bring examples and methods on how to use the
different modules (any contribution on this would be very welcome, too).
Finally, the code provided in thetest/subdirectory is also representative on
how to use the different modules.Basically, a pycrate's object exposes the following methods:set_val()/get_val()/get_val_d(), which sets value into and gets value from the objectfrom_bytes()/to_bytes(), which converts a buffer into values according to the internal structure of the object, and backfrom_json()/to_json(), for working with JSON-encoded valueshex()/bin(), for getting hexadecimal and binary representation of the serialized obect's valuerepr()/show(), for providing nice python's internal representation, and printable representation of the object's valueASN.1 usageWhen a Python module frompycrate_asn1dir/is loaded, it creates Python classes
corresponding to ASN.1 modules (all dash characters are converted to underscore).
Each ASN.1 object has a corresponding Python instance, exposing the following methods:from_asn1()/to_asn1(), which converts ASN.1 textual value to Python value and backfrom_aper()/to_aper(), which converts aligned PER encoded value to Python value and backfrom_uper()/to_uper(), which converts unaligned PERfrom_ber()/to_ber(), which converts BERfrom_cer()/to_cer(), which converts CERfrom_der()/to_der(), which converts DERfrom_jer()/to_jer(), which converts JERfrom_oer()/to_oer(), which converts OERfrom_coer()/to_coer(), which converts canonical OERset_val()/get_val()to set and get Python's values into the ASN.1 objectget_proto()to return to internal structure of the ASN.1 objectAll the methods useful for working with ASN.1 objects at runtime can be found in
the filepycrate_asn1rt/asnobj.py.ToolsFour different tools are provided (yet):pycrate_showmedia.pyparses some media files (jpg, bmp, gif, mp3, png,
tiff, mpeg4) and pretty print the file structure on the standard output.pycrate_asn1compile.pycompiles ASN.1 source file(s) and produce a Python
source file that makes use of the ASN.1 runtime. This source file is then
usable to encode / decode any ASN.1 object from the compiled ASN.1
specification.pycrate_berdecode.pyparses any BER/CER/DER encoded binary value of ASN.1
objects and prints the corresponding structure.pycrate_map_op_info.pyprints prototypes and various information related to
TCAP-MAP (Mobile Application Part) and CAMEL operations and application-contexts.pycrate_gtp_type_info.pyprints prototypes and various information related to
GTP messages and transactions as in version 0, 1 or 2ExamplesIt is possible to test thepycrate_showmedia.pytool with media test files
provided in./test/res/, or any other supported media file.$./tools/pycrate_showmedia.py--helpusage: pycrate_showmedia.py [-h] [-bl BL] [-wt] inputprint the internal structure of the input media file,supported formats are:BMP, GIF, JPEG, MP3, MPEG4, PNG, TIFFpositional arguments:input       input media fileoptional arguments:-h, --help  show this help message and exit-bl BL      maximum length for buffer representation-wt         show also absent / transparent fields$./tools/pycrate_showmedia.py./test/res/xkcd_wireless_signal.png### PNG ###<sig [PNG signature] : '\x89PNG\r\n\x1a\n'>### PNGBody ###### PNGChunk ###<len : 13><type : 'IHDR'>### IHDR ###<width : 238><height : 415><depth [bit depth] : 8><color [color type] : 0 (Greyscale)><comp [compression method] : 0 (inflate/deflate with sliding window)><filter [filter method] : 0 (no interlace)><interlace [interlace method] : 0 (no interlace)><crc : 0x7d8cb12e>### PNGChunk ###<len : 9><type : 'pHYs'><data :00 00 0c 4e 00 00 0c 4e 01                      | '\x00\x00\x0cN\x00\x00\x0cN\x01'><crc : 0x7f778c23>### PNGChunk ###<len : 792><type : 'iCCP'><data :50 68 6f 74 6f 73 68 6f 70 20 49 43 43 20 70 72 | 'Photoshop ICC pr'6f 66 69 6c 65 00 00 78 da 63 60 60 9e e0 e8 e2 | 'ofile\x00\x00x\xdac``\x9e\xe0\xe8\xe2'[...]32 fd fc ea eb 82 ef e1 3f 05 7e 9d fa d3 fa cf | '2\xfd\xfc\xea\xeb\x82\xef\xe1?\x05~\x9d\xfa\xd3\xfa\xcf'f1 ff 7f 00 0d 00 0f 34                         | '\xf1\xff\x7f\x00\r\x00\x0f4'><crc : 0xfa96f15d>### PNGChunk ###<len : 32><type : 'cHRM'><data :00 00 6e 27 00 00 73 af 00 00 df f2 00 00 83 30 | "\x00\x00n'\x00\x00s\xaf\x00\x00\xdf\xf2\x00\x00\x830"00 00 77 43 00 00 c8 0a 00 00 34 95 00 00 2e dc | '\x00\x00wC\x00\x00\xc8\n\x00\x004\x95\x00\x00.\xdc'><crc : 0x20bf171a>### PNGChunk ###<len : 21130><type : 'IDAT'><data :78 da ed bd 79 50 8d fd 1f ff ff bc ce 39 73 4e | 'x\xda\xed\xbdyP\x8d\xfd\x1f\xff\xff\xbc\xce9sN'db b4 37 95 32 b4 19 94 06 2d 7e 11 26 b2 fc 10 | '\xdb\xb47\x952\xb4\x19\x94\x06-~\x11&\xb2\xfc\x10'[...]91 a3 d8 5b fc e1 cb 51 fd ab fb c9 cc ec ee 21 | '\x91\xa3\xd8[\xfc\xe1\xcbQ\xfd\xab\xfb\xc9\xcc\xec\xee!'7d 70 6e f3 18 ce c1 c1 6d 8c 81 44 32 cf 51 ba | '}pn\xf3\x18\xce\xc1\xc1m\x8c\x81D2\xcfQ\xba'...><crc : 0xa9fbdd38>### PNGChunk ###<len : 0><type : 'IEND'><data : ><crc : 0xae426082>It is possible to test thepycrate_asn1compile.pytool with some test ASN.1
specification from./test/res/, or any other valid ASN.1 specification of your
choice.$./tools/pycrate_asn1compile.py--helpusage: pycrate_asn1compile.py [-h] [-s SPEC] [-i INPUT [INPUT ...]] [-o OUTPUT] [-g GENERATOR_PATH] [-j] [-fautotags] [-fextimpl] [-fverifwarn]compile ASN.1 input file(s) for the pycrate ASN.1 runtimeoptional arguments:-h, --help            show this help message and exit-s SPEC               provide a specification shortname, instead of ASN.1 input file(s)-i INPUT [INPUT ...]  ASN.1 input file(s) or directory-o OUTPUT             compiled output Python (and json) source file(s)-g GENERATOR_PATH, --generator GENERATOR_PATHprovide an alternative python generator file path-j                    output a json file with information on ASN.1 objects dependency-fautotags            force AUTOMATIC TAGS for all ASN.1 modules-fextimpl             force EXTENSIBILITY IMPLIED for all ASN.1 modules-fverifwarn           force warning instead of raising during the verification stage$./tools/pycrate_asn1compile.py-i./test/res/Hardcore.asn-oHardcore[proc] [./test/res/Hardcore.asn] module HardcoreSyntax (oid: []): 116 ASN.1 assignments found--- compilation cycle ------ compilation cycle ------ compilation cycle ------ verifications ---[proc] ASN.1 modules processed: ['HardcoreSyntax'][proc] ASN.1 objects compiled: 75 types, 3 sets, 37 values[proc] doneAfter compiling a module, it is possible to load it in Python and use it for
encoding / decoding any objects defined in it.Python3.8.5(default,Jul282020,12:59:40)[GCC9.3.0]onlinuxType"help","copyright","credits"or"license"formoreinformation.>>>fromHardcoreimportHardcoreSyntax>>>HardcoreSyntax# this is the only ASN.1 module provided in Hardcore.asn<class'Hardcore.HardcoreSyntax'>>>>Final=HardcoreSyntax.Final# this is the Final object defined at line 115>>>Final<Final(SEQUENCE)>>>>Final.get_proto()# warning: this can return very laaaaaaarge definitions('SEQUENCE',{w1:('SEQUENCE',{r10:('SEQUENCE',{low:'INTEGER',high:'INTEGER',bool:'BOOLEAN',null(OPT):'NULL'}),r90:('SEQUENCE',{low:'INTEGER',high:'INTEGER',bool:'BOOLEAN',null(OPT):'NULL'})}),w2:('SEQUENCE',{r10:('SEQUENCE',{low:'INTEGER',high:'INTEGER',bool:'BOOLEAN',null(OPT):'NULL'}),r90:('SEQUENCE',{low:'INTEGER',high:'INTEGER',bool:'BOOLEAN',null(OPT):'NULL'})}),bool:'BOOLEAN'})>>>V={...'w1':{'r10':{'low':5,'high':50,'bool':False},'r90':{'low':50,'high':95,'bool':False,'null':0}},...'w2':{'r10':{'low':1,'high':10,'bool':False},'r90':{'low':90,'high':100,'bool':True}},...'bool':True}>>>Final.set_val(V)>>>print(Final.to_asn1())# .to_asn1() returns a printable ASN.1 representation of the value{w1{r10{low5,high50,boolFALSE},r90{low50,high95,boolFALSE,nullNULL}},w2{r10{low1,high10,boolFALSE},r90{low90,high100,boolTRUE}},boolTRUE}>>>Final.to_aper()# aligned PERb'*\x85\x92\x80@\x01\x00\x08\x02\xd5`'>>>Final.to_uper()# unaligned PERb'*\x85\x92\x80@@\x02\x00\xb5X'>>>Final.to_ber()b'05\xa0\x18\xa0\t\x80\x01\x05\x81\x012\x82\x01\x00\xa1\x0b\x80\x012\x81\x01_\x82\x01\x00\x83\x00\xa1\x16\xa0\t\x80\x01\x01\x81\x01\n\x82\x01\x00\xa1\t\x80\x01Z\x81\x01d\x82\x01\xff\x82\x01\xff'>>>Final.to_cer()b'0\x80\xa0\x80\xa0\x80\x80\x01\x05\x81\x012\x82\x01\x00\x00\x00\xa1\x80\x80\x012\x81\x01_\x82\x01\x00\x83\x00\x00\x00\x00\x00\xa1\x80\xa0\x80\x80\x01\x01\x81\x01\n\x82\x01\x00\x00\x00\xa1\x80\x80\x01Z\x81\x01d\x82\x01\xff\x00\x00\x00\x00\x82\x01\xff\x00\x00'>>>Final.to_der()b'05\xa0\x18\xa0\t\x80\x01\x05\x81\x012\x82\x01\x00\xa1\x0b\x80\x012\x81\x01_\x82\x01\x00\x83\x00\xa1\x16\xa0\t\x80\x01\x01\x81\x01\n\x82\x01\x00\xa1\t\x80\x01Z\x81\x01d\x82\x01\xff\x82\x01\xff'>>>Final.from_ber(Final.to_ber())>>>Final()==V# or Final._val == VTrueFor more information about the API exposed for each ASN.1 object, you can check
the docstrings of all ASN.1 objects, and also read the source filepycrate_asn1rt/asnobj.py.
Do not forget to have a look at theWiki, too!