def ISLOGICAL(value):
  """
  Checks whether a value is `True` or `False`.

  >>> ISLOGICAL(True)
  True
  >>> ISLOGICAL(False)
  True
  >>> ISLOGICAL(0)
  False
  >>> ISLOGICAL(None)
  False
  >>> ISLOGICAL("Test")
  False
  """
  return isinstance(value, bool)