docs: def encode(self, variables, attributes):
          """
          Encode the variables and attributes in this store
  
          Parameters
          ----------
          variables : dict-like
              Dictionary of key/value (variable name / xr.Variable) pairs
          attributes : dict-like
              Dictionary of key/value (attribute name / attribute) pairs
  
          Returns
          -------
          variables : dict-like
          attributes : dict-like
  
          """
          variables = OrderedDict([(k, self.encode_variable(v))
                                   for k, v in variables.items()])
          attributes = OrderedDict([(k, self.encode_attribute(v))
                                    for k, v in attributes.items()])
          return variables, attributes