def print_usage(self, file=None):
if self.usage:<EOL><INDENT>print(self.get_usage(), file=file)<EOL><DEDENT>
print_usage(file : file = stdout)

        Print the usage message for the current program (self.usage) to
        'file' (default stdout).  Any occurrence of the string "%prog" in
        self.usage is replaced with the name of the current program
        (basename of sys.argv[0]).  Does nothing if self.usage is empty
        or not defined.