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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 improve_model_docstring(app, what, name, obj, options, lines):
 """Hook that improves the autodoc docstrings for Django models. :type app: sphinx.application.Sphinx :param what: The parent type, ``class`` or ``module`` :type what: str :param name: The dotted path to the child method/attribute. :type name: str :param obj: The Python object that i s being documented. :param options: The current autodoc settings. :type options: dict :param lines: The current documentation lines :type lines: list """

    if what == 'class':
        _improve_class_docs(app, obj, lines)
    elif what == 'attribute':
        _improve_attribute_docs(obj, name, lines)
    elif what == 'method':
        _improve_method_docs(obj, name, lines)

    # Return the extended docstring
    return lines