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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 Validate(self, value, **_):
 """Validates a python format representation of the value."""

    if isinstance(value, rdfvalue.RDFString):
      # TODO(hanuszczak): Use `str` here.
      return Text(value)

    if isinstance(value, Text):
      return value

    if isinstance(value, bytes):
      return value.decode("utf-8")

    raise type_info.TypeValueError("Not a valid unicode string: %r" % value)