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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 napoleon_to_sphinx(docstring, **config_params):
 """ Convert napoleon docstring to plain sphinx string. Args: docstring (str):
 Docstring in napoleon format. **config_params (dict):
 Whatever napoleon doc configuration you want. Returns: str: Sphinx string. """

    if "napoleon_use_param" not in config_params:
        config_params["napoleon_use_param"] = False

    if "napoleon_use_rtype" not in config_params:
        config_params["napoleon_use_rtype"] = False

    config = Config(**config_params)

    return str(GoogleDocstring(docstring, config))