def _is_same_value_at_column(i, all_args):
    """ comparison from both ends so as to find opportunistically that the parameter is not the same everywhere"""
    left, right = 1, len(all_args) - 1
    value = all_args[0][i]
    while True:
        if value != all_args[left][i]:
            return False
        left += 1
        if value != all_args[right][i]:
            return False
        right -= 1
        if left > right:
            break
    return True
