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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 intersection(source, mask):
 """Intersect two layers. Issue https://github.com/inasafe/inasafe/issues/3186 :param source: The vector layer to clip. :type source: QgsVectorLayer :param mask: The vector layer to use for clipping. :type mask: QgsVectorLayer :return: The clip vector layer. :rtype: QgsVectorLayer .. versionadded:: 4.0 """

    output_layer_name = intersection_steps['output_layer_name']
    output_layer_name = output_layer_name % (
        source.keywords['layer_purpose'])

    parameters = {'INPUT': source,
                  'OVERLAY': mask,
                  'OUTPUT': 'memory:'}

    # TODO implement callback through QgsProcessingFeedback object

    initialize_processing()

    feedback = create_processing_feedback()
    context = create_processing_context(feedback=feedback)
    result = processing.run('native:intersection', parameters, context=context)
    if result is None:
        raise ProcessingInstallationError

    intersect = result['OUTPUT']
    intersect.setName(output_layer_name)
    intersect.keywords = dict(source.keywords)
    intersect.keywords['title'] = output_layer_name
    intersect.keywords['layer_purpose'] = \
        layer_purpose_exposure_summary['key']
    intersect.keywords['inasafe_fields'] = \
        dict(source.keywords['inasafe_fields'])
    intersect.keywords['inasafe_fields'].update(
        mask.keywords['inasafe_fields'])
    intersect.keywords['hazard_keywords'] = \
        dict(mask.keywords['hazard_keywords'])
    intersect.keywords['exposure_keywords'] = dict(source.keywords)
    intersect.keywords['aggregation_keywords'] = dict(
        mask.keywords['aggregation_keywords'])

    check_layer(intersect)
    return intersect