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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 format_kwargs(attrs, params):
 """Modify attribute with argument values. Parameters attrs : dict Attributes to be assigned to function output. The values of the attributes in braces will be replaced the the corresponding args values. params : dict A BoundArguments.arguments dictionary storing a function's arguments. """

    attrs_mapping = {'cell_methods': {'YS': 'years', 'MS': 'months'},
                     'long_name': {'YS': 'Annual', 'MS': 'Monthly'}}

    for key, val in attrs.items():
        mba = {}
        # Add formatting {} around values to be able to replace them with _attrs_mapping using format.
        for k, v in params.items():
            if isinstance(v, six.string_types) and v in attrs_mapping.get(key, {}).keys():
                mba[k] = '{' + v + '}'
            else:
                mba[k] = v

        attrs[key] = val.format(**mba).format(**attrs_mapping.get(key, {}))