def remove_pkcs1v15_signature_padding(key_length, data):
if _backend != '<STR_LIT>':<EOL><INDENT>raise SystemError(pretty_message(<EOL>'''<STR_LIT>'''<EOL>))<EOL><DEDENT>return _remove_pkcs1v15_padding(key_length, data, '<STR_LIT>')<EOL>
Removes PKCS#1 v1.5 padding from a signed message using constant time
operations

:param key_length:
    An integer of the number of bytes in the key

:param data:
    A byte string to unpad

:return:
    The unpadded data as a byte string