code: def alias(self, maps):
          
          for k, v in maps.items():  # pylint: disable=invalid-name
              if self.verbose_mode:
                  print(
                      " * Mapping a specified var as a alias:"
                      " {0} -> {1}".format(v, k))
              self.app.config[v] = self.app.config[k]
docs: Examples:
              Make alias var -> as.
  
              >>> env.alias(maps={
                'TEST_DATABASE_URL': 'SQLALCHEMY_DATABASE_URI',
                'TEST_HOST': 'HOST'
              })