ph-schematron/src/main/java/com/helger/schematron/pure/exchange/PSReader.java
@Nullable
  private static String _getAttributeValue (@Nullable final String sAttrValue)
  {
    return sAttrValue == null ? null : sAttrValue.trim ();
  }
@Nullable
  private static String _getAttributeValue (@Nullable final String sAttrValue)
  {
    return sAttrValue == null ? null : sAttrValue.trim ();
  }
Utility method to get a real attribute value, by trimming spaces, if the
value is non-<code>null</code>.

@param sAttrValue
The source attribute value. May be <code>null</code>.
@return <code>null</code> if the input parameter is <code>null</code>.