code: def required_validator(validator, req, instance, schema):
      
      if schema.get('paramType'):
          if req is True and not instance:
              return [ValidationError("%s is required" % schema['name'])]
          return []
      return _validators.required_draft4(validator, req, instance, schema)
docs: Swagger 1.2 expects `required` to be a bool in the Parameter object, but
      a list of properties in a Model object.