函数调用过程图解 def happy(): def main(): def sing(person): person ="Fred" happy ( print "Happy Birthday to you!" sing("Fred") print happy ( print "Happy birthday,dear",person +". sing("Lucy") happy() person: "Fred" def main () person "Fred" def sing(person): sing("Fred") happy() print happy() sing("Lucy") print "Happy birthday,dear",person +". happy() def main(): def sing(person): sing("Fred") happy() print 农exson#"Lucy happy() sing("Lucy") print "Happy birthday,dear",person +". happy() person "Lucy"函数调用过程图解