<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def append_original_doc(parent, num=0):
 """Return an iterator that append the docstring of the given `parent` function to the applied function"""

    def func(func):
        func.__doc__ = func.__doc__ and func.__doc__ + indent(
            parent.__doc__, num)
        return func
    return func