Python switch/case Replacement

#Slightly advanced version of this.
# It works if the person enters Y, YES, Yes, yES, and so on for
# Yes, No, True, and False.
# The key to this is on two parts.
#    1) There is the dictionary names switch.  This is so named
#       because I am using it like it is a switch statement in
#       other languages.
#    2) The switch.get(user_input.lower()) part is the other key.
#       It takes what the user put in and converts it to lower
#       case, then tests it against the dictionary.  If there is
#       a match, it returns True or False as a boolian.  Otherwise
#       it returns the special type of None and the while loop
#       continues.

## Test run results:
##
##>>>
##Is Lelis Online ? Answer True or False : g
##Just answer 'True' or 'False'
##
##Is Lelis Online ? Answer True or False : t
##Hi! Desculpa o atraso; ainda podemos fazer algo?
##>>> ===================================== RESTART =====================================
##>>>
##Is Lelis Online ? Answer True or False : FaLsE
##Sorry! I totally forget you. Muito contente por encontrar um crioulo. Keep in touch.
##>>>

user_input=None
switch = {'true':True,'t':True,'yes':True,'y':True,'false':False,'f':False,'no':False,'n':False}
while user_input==None:
    user_input=raw_input("Is Lelis Online ? Answer True or False : ")
    user_input=switch.get(user_input.lower())
    if user_input==None:
        print "Just answer 'True' or 'False'\n"

if user_input == True:
    print "Hi! Desculpa o atraso; ainda podemos fazer algo?"
else:
    print "Sorry! I totally forget you. Muito contente por encontrar um crioulo. Keep in touch."