There are several ways an ASN.1 BIT STRING may be represented in Python:
osyspyrt.asn1univtype.Asn1BitString
This is the type that decoding will produce by default. It combines binary data with the number of bits in the BIT STRING. This class provides attributes and methods useful in manipulating the value either as a sequence of bytes or as a sequence of bits.
bytes or bytearray object
Either of these can be used to provide data for encoding. The BIT STRING will include all bits of the given value.
An instance of a generated class. This applies when the BIT STRING is defined with named bits, as described below.