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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 parse_filter_params(query_params, filterable):
 """ Parse query_params to a filter params dict. Merge multiple values for one key to a list. Filter out keys that aren't filterable. :param query_params: query params :param filterable: list of filterable keys :return: dict of filter values """

    if query_params is not None:
        filter_params = {}
        for fq in query_params.mixed():
            if fq in filterable:
                filter_params[fq] = query_params.mixed().get(fq)
        return filter_params
    else:
        return {}