Returns the hours component of an xs:time.
fn:hours-from-time( $arg as xs:time?xs:integer?If $arg is the empty sequence, the function returns the empty sequence.
Otherwise, the function returns an xs:integer between 0 and 23, both
inclusive, representing the value of the hours component in the local value of
$arg.
Assume that the dynamic context provides an implicit timezone value of
-05:00.
The expression fn:hours-from-time(xs:time("11:23:00")) returns 11.
The expression fn:hours-from-time(xs:time("21:23:00")) returns 21.
The expression fn:hours-from-time(xs:time("01:23:00+05:00")) returns 1.
The expression fn:hours-from-time(fn:adjust-time-to-timezone(xs:time("01:23:00+05:00"),
xs:dayTimeDuration("PT0S"))) returns 20.
The expression fn:hours-from-time(xs:time("24:00:00")) returns 0.
