code: public Set<NewGTFSError> checkReferencesAndUniqueness(String keyValue, int lineNumber,
          Field field, String value, Table table) {
          return checkReferencesAndUniqueness(keyValue, lineNumber, field, value, table,
              table.getKeyFieldName(), table.getOrderFieldName());
      }
docs: During table load, checks the uniqueness of the entity ID and that references are valid.
  NOTE: This method defaults the key field and order field names to this table's values.
  
  @param keyValue   key value for the record being checked
  @param lineNumber line number of the record being checked
  @param field      field currently being checked
  @param value      value that corresponds to field
  @param table      table currently being checked
  @return any duplicate or bad reference errors.