#NEWLINE# @ property #NEWLINE# def duration( self ) : #NEWLINE# #INDENT# '\n        Return the duration (in milliseconds) that this item was in-progress.\n        ' #NEWLINE# if ( self . date_started and self . date_finished ) : #NEWLINE# #INDENT# duration = ( ( self . date_finished - self . date_started ) . total_seconds ( ) * 1000 ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# duration = None #NEWLINE# #UNINDENT# return duration