def _get_spec_for_keyword(t_spec, key):
    """Grabs the var tuple for a specific key.
    Needed since variable name is in tuple
    :param t_spec: Thrift spec for function/class
    :param key: Variable key name to get
    :return: None or spec tuple
    """
    for _, arg_spec in t_spec.items():
        if arg_spec[1] == key:
            return arg_spec
    return None