docs: def get_field_values(self, name, maxvalues=-1, sort=True, **query_dict):
          """Retrieve the unique values for a field, along with their usage counts.
  
          :param name: Name of field for which to retrieve values
          :type name: string
  
          :param sort: Sort the result
  
          :param maxvalues: Maximum number of values to retrieve. Default is -1,
            which causes retrieval of all values.
          :type maxvalues: int
  
          :returns: dict of {fieldname: [[value, count], ... ], }
  
          """
          param_dict = query_dict.copy()
          param_dict.update(
              {
                  'rows': '0',
                  'facet': 'true',
                  'facet.field': name,
                  'facet.limit': str(maxvalues),
                  'facet.zeros': 'false',
                  'facet.sort': str(sort).lower(),
              }
          )
          resp_dict = self._post_query(**param_dict)
          result_dict = resp_dict['facet_counts']['facet_fields']
          result_dict['numFound'] = resp_dict['response']['numFound']
          return result_dict