#NEWLINE# @ classmethod #NEWLINE# def valid_child_of( cls , parent , obj = None ) : #NEWLINE# #INDENT# if ( obj and obj . get_parent ( ) ) : #NEWLINE# #INDENT# return ( parent in parent . get_children ( ) ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# return isinstance ( parent , TableHeader )