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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 create_filter(request, mapped_class, geom_attr, **kwargs):
 """ Create MapFish default filter based on the request params. Arguments: request the request. mapped_class the SQLAlchemy mapped class. geom_attr the key of the geometry property as defined in the SQLAlchemy mapper. If you use ``declarative_base`` this is the name of the geometry attribute as defined in the mapped class. \\**kwargs additional arguments passed to ``create_geom_filter()``. """

    attr_filter = create_attr_filter(request, mapped_class)
    geom_filter = create_geom_filter(request, mapped_class, geom_attr,
                                     **kwargs)
    if geom_filter is None and attr_filter is None:
        return None
    if geom_filter is None:
        return attr_filter
    if attr_filter is None:
        return geom_filter
    return and_(geom_filter, attr_filter)