trouble understanding None

[Jakle]

I'm trying to write a program (with my very limited knowledge of python)
that will convert text I type into those letters drawn with ascii symbols. I
did 2 letters then went to test it. Here's the code I have so far:

*******************************************
def S():
    print    "  ________  "
    print    " /--------\ "
    print    "//        \\"
    print    "||        ^^"
    print    "||          "
    print    "\\________  "
    print    " \--------\ "
    print    "          \\"
    print    "          ||"
    print    "_         ||"
    print    "\\________//"
    print    " \--------/ ",

def T():
    print    "______________"
    print    "------  ------"
    print    "      ||      "
    print    "      ||      "
    print    "      ||      "
    print    "      ||      "
    print    "      ||      "
    print    "      ||      "
    print    "      ||      "
    print    "      ||      "

print S(), T()
*******************************************

WOW, that came out weird, but if you copy/paste it into idle it looks fine.
That an "S" and a "T". Anyways, The idea is to have a function for each
letter, then use a for loop and a ton of if statements to traverse and print
the letters/functions. I understand that I might be doing too much work to
do this, but I'm trying to practice what I am learning. OK, the test prints
the letters, but also prints "None" at the end of each function. I don't
understand it. I'm reading "How To Think Like A Computer Scientist: Learning
With Python", and it only has one little paragraph about the "None" return
value, and that's only regarding conditional statements. If someone could
throw some wisdom my way I'm be very greatful. Thanks ahead of time.