'Base64 decode, gunzip, return string.
:param encoded_data: The data that (most likely) comes from a base64://
string stored in the profile. It MUST CONTAIN
the base64:// specification at the beginning.
:return: The decoded data'

def decode_b64_data(self, encoded_data):

    encoded_data = encoded_data[len(self.DATA_PROTO):]
    encoded_data = base64.b64decode(encoded_data)
    return encoded_data.decode('zlib')
