code: def build_db_query(fields_names, field_values):
      
      if isinstance(field_values, string_types):
          field_values = [field_values]
  
      if len(fields_names) != len(field_values):
          raise ValueError('Error: unable to build a primary key query due '
                           'to mismatch in number of fields {0} vs {1}'
                           .format(len(fields_names), len(field_values)))
  
      query = dict()
      for k, v in zip(fields_names, field_values):
          query[k] = v
      return query
docs: method builds query dictionary by zipping together DB field names with the field values