uration</a>.</p>
 
 <p>The datatype <code>xdt:dayTimeDuration</code> is a subtype of <code>xs:duration</code>
 whose lexical representation contains only day, hour, minute, and second components.
 This datatype resides in the namespace <code>http://www.w3.org/2003/11/xpath-datatypes</code>.</p>
 
 <p>The XML Schema specification states that values can be of an arbitrary size.
 Implementations may chose not to or be incapable of supporting arbitrarily large and/or small values.
 An <CODE>UnsupportedOperation