#NEWLINE# def observe( self , observer ) : #NEWLINE# #INDENT# if isinstance ( observer , collections . Callable ) : #NEWLINE# #INDENT# self . __observers . append ( observer ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# print ( ( 'Event Error: %s not callable' % repr ( observer ) ) ) #NEWLINE# #UNINDENT# return self