Importing again and again

[abcd]

If I have code which imports a module over and over again...say each
time a function is called, does that cause Python to actually re-import
it...or will it skip it once the module has been imported??

for example:

def foo():
    import bar
    bar.printStuff()

foo()
foo()
foo()
foo()

...will that re-import bar 4 times...or just import it once?  is this a
big performance hit?

thanks