code: private SingularAttribute<X, ?> getDeclaredSingularAttribute(String paramString, boolean checkValidity)
      {
          SingularAttribute<X, ?> attribute = null;
          if (declaredSingluarAttribs != null)
          {
              attribute = declaredSingluarAttribs.get(paramString);
          }
  
          if (checkValidity)
          {
              checkForValid(paramString, attribute);
          }
          return attribute;
      }
docs: Returns declared singular attribute.
  
  @param paramString
  the param string
  @param checkValidity
  the check validity
  @return the declared singular attribute