fix akamaized cipher regex, note attribute filtering in readme

README.md

@@ -193,7 +193,7 @@ If you need to optimize for a specific feature, such as the "highest resolution"
 ```python
 >>> yt.streams.filter(progressive=True).order_by('resolution').desc().all()
 ```
-Note that ``order_by`` cannot be used if your attribute is undefined in any of the Stream instances, so be sure to apply a filter to remove those before calling it.
+Note: Using ``order_by`` on a given attribute will filter out all streams missing that attribute.
 
 ### Callbacks
 

pytube/cipher.py

@@ -41,7 +41,7 @@ def get_initial_function_name(js):
         r'(?P<sig>[a-zA-Z0-9$]+)\s*=\s*function\(\s*a\s*\)\s*{\s*a\s*=\s*a\.split\(\s*""\s*\)',  # noqa: E501
         r'(["\'])signature\1\s*,\s*(?P<sig>[a-zA-Z0-9$]+)\(',
         r"\.sig\|\|(?P<sig>[a-zA-Z0-9$]+)\(",
-        r"yt\.akamaized\.net/\)\s*\|\|\s*.*?\s*[cs]\s*&&\s*[adf]\.set\([^,]+\s*,\s*(?:encodeURIComponent\s*\()?\s*(?P<si$",  # noqa: E501
+        r'yt\.akamaized\.net/\)\s*\|\|\s*.*?\s*[cs]\s*&&\s*[adf]\.set\([^,]+\s*,\s*(?:encodeURIComponent\s*\()?\s*(?P<sig>[a-zA-Z0-9$]+)\(',  # noqa: E501
         r"\b[cs]\s*&&\s*[adf]\.set\([^,]+\s*,\s*(?P<sig>[a-zA-Z0-9$]+)\(",  # noqa: E501
         r"\b[a-zA-Z0-9]+\s*&&\s*[a-zA-Z0-9]+\.set\([^,]+\s*,\s*(?P<sig>[a-zA-Z0-9$]+)\(",  # noqa: E501
         r"\bc\s*&&\s*a\.set\([^,]+\s*,\s*\([^)]*\)\s*\(\s*(?P<sig>[a-zA-Z0-9$]+)\(",  # noqa: E501