Taking into consideration the [3.5 edition rules](http://www.dandwiki.com/wiki/SRD:Ability_Scores#Table:_Ability_Modifiers_and_Bonus_Spells), your goal is to build a function that takes an ability score (worry not about validation: it is always going to be a non negative integer), will return:

* attribute modifier, as indicated on the table of the above link;
* maximum spell level for the spells you can cast (-1 for no spells at all) with that score;
* the eventual extra spells you might get (as an array/list, with elements representing extra spells for 1st, 2nd,... spell level in order; empty array for no extra spells).

The result needs to be an object (associative array in PHP), as shown in the examples:

```python
char_attribute(0) == {"modifier": 0, "maximum_spell_level": -1, "extra_spells": []}
char_attribute(1) == {"modifier": -5, "maximum_spell_level": -1, "extra_spells": []}
char_attribute(5) == {"modifier": -3, "maximum_spell_level": -1, "extra_spells": []}
char_attribute(10) == {"modifier": 0, "maximum_spell_level": 0, "extra_spells": []}
char_attribute(20) == {"modifier": +5, "maximum_spell_level": 9, "extra_spells": [2,1,1,1,1]}
```

*Note: I didn't explain things in detail and just pointed out to the table on purpose, as my goal is also to train the pattern recognition skills of whoever is going to take this challenges, so do not complain about a summary description. Thanks :)*

In the same series:

* [D&D Character generator #1: attribute modifiers and spells](https://www.codewars.com/kata/d-and-d-character-generator-number-1-attribute-modifiers-and-spells/)
* [D&D Character generator #2: psion power points](https://www.codewars.com/kata/d-and-d-character-generator-number-2-psion-power-points/)
* [D&D Character generator #3: carrying capacity](https://www.codewars.com/kata/d-and-d-character-generator-number-3-carrying-capacity/)

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = 'from math import ceil;char_attribute=lambda n: (lambda m: {"modifier": n and m, "maximum_spell_level": -1 if n<10 else min([n-10,9]), "extra_spells": [e for e in [(lambda s: s if s>0 else None)(ceil((m-i)/4)) for i in range(9)] if e!=None]})(n//2-5 if n else -1)'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'char_attribute'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 6420