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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _ValidateAFF4Type(aff4_type):
 """Validates an AFF4 type."""

  if aff4_type is None:
    return

  if not isinstance(aff4_type, type):
    raise TypeError("aff4_type=%s must be a type" % aff4_type)
  if not issubclass(aff4_type, AFF4Object):
    raise TypeError("aff4_type=%s must be a subclass of AFF4Object." %
                    aff4_type)