python in the upper, lower usage

#upper () String uppercase letter lowercase
#lower () String uppercase to lowercase letters

S = >>> ' the Hello World! ' 
>>> s.upper ()
 ' HELLO WORLD! ' 
>>> s.lower ()
 ' the Hello world! ' 
>>> s.capitalize ()       # capitalized 
' the Hello world! ' 
>>> s.lower (). title ()    # title () for each word capitalized