Add the print "Hi" in an if __name__ == "__main__" clause.
When python imports modules it executes the code contained in them in order to build the module namespace. If you run the module as the main script the __name__ is going to get assigned to __main__ and the code inside the if clause is going to get executed.
Since you're not running the script as the main script the __name__ gets assigned to the modules __name__ (in this case file1) and as a result this test will not succeed and the print statement is not going to get executed.
def run():
# Do something
if __name__ == "__main__":
print "Hi"