def is_uid(uid):
if not isinstance(uid, str):<EOL><INDENT>return False<EOL><DEDENT>if uid != "<STR_LIT:0>" and len(uid) != <NUM_LIT:32>:<EOL><INDENT>return False<EOL><DEDENT>return True<EOL>
Checks if the passed in uid is a valid UID

    :param uid: The uid to check
    :type uid: string
    :return: True if the uid is a valid 32 alphanumeric uid or '0'
    :rtype: bool