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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def list_functions(mod_name):
 """Lists all functions declared in a module. http://stackoverflow.com/a/1107150/3004221 Args: mod_name: the module name Returns: A list of functions declared in that module. """

    mod = sys.modules[mod_name]
    return [func.__name__ for func in mod.__dict__.values()
            if is_mod_function(mod, func)]