#NEWLINE# def full_clean( self , * args , **kw ) : #NEWLINE# #INDENT# if ( not isrange ( self . start_date , self . end_date ) ) : #NEWLINE# #INDENT# raise ValidationError ( _ ( 'Date period ends before it started.' ) ) #NEWLINE# #UNINDENT# super ( DatePeriod , self ) . full_clean ( * args , ** self )