code: def Validate(self):
      
      # All filters can handle the input type.
      bad_filters = []
      for f in self.filters:
        try:
          f.Validate()
        except DefinitionError as e:
          bad_filters.append("%s: %s" % (f.expression, e))
      if bad_filters:
        raise DefinitionError(
            "Filters with invalid expressions: %s" % ", ".join(bad_filters))
docs: Verifies this filter set can process the result data.