code: def license_or_special(self, lic):
          
          if isinstance(lic, utils.NoAssert):
              return self.spdx_namespace.noassertion
          elif isinstance(lic, utils.SPDXNone):
              return self.spdx_namespace.none
          else:
              return self.create_license_node(lic)
docs: Check for special values spdx:none and spdx:noassertion.
          Return the term for the special value or the result of passing
          license to create_license_node.