def METHOD_NAME(mat):
    """
    Check if a Distance Matrix is symmetric.
    Equivalent to not (mat.T != mat).any()
    Parameters
    ----------
    mat : 2D array_like
        Distance matrix.
    Result:
    -------
    is_symmetric: Boolean
        not (mat.T != mat).any()
    """
    # the is_hollow check is really cheap,
    # so can reuse is_symmetric_and_hollow
    return is_symmetric_and_hollow(mat)[0]