'Returns the streaming member\'s shape if any; or None otherwise.'

def _get_streaming_body(self, shape):

    if (shape is None):
        return None
    payload = shape.serialization.get('payload')
    if (payload is not None):
        payload_shape = shape.members[payload]
        if (payload_shape.type_name == 'blob'):
            return payload_shape
    return None
