code: protected Date getDateParam(String paramName, String errorMessage) throws IOException {
          return getDateParam(paramName, errorMessage, (Map<String, Object>) inputParams.get());
      }
docs: Parses a date from either dd/MM/yyyy or yyyy-MM-dd format. Uses the default parameter inputmap.
  
  @param paramName    the name of the parameter containing the date
  @param errorMessage the message to put in an error if one occurs
  @return a date object correcponding with the jsonobject
  @throws IOException If something went wrong