def _in_while_loop(control_flow_node_map, op_name):
    """
    Check if a given control flow operator is part of a while loop execution
    frame. This is based on the fact that there is only one occurrence of
    `LoopCond` for a loop execution frame and it is only presented in the loop
    construct.

    Parameters
    ----------
    control_flow_node_map : Dict[str, Set[str]]
        A dictionay contains the unique control flow execution frame name to
        a set of primitive operators mapping.

    op_name : str
        The name of a control flow primitive.

    Returns
    -------
    ret : bool
        Return true if the operator is in a while loop execution frame,
    otherwise, return false.
    """
    return op_name in control_flow_node_map and "LoopCond" in control_flow_node_map[op_name]