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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 layer_hazard_classification(layer):
 """Returned this particular hazard classification. :param layer: hazard layer or exposure layer :type layer: qgis.core.QgsVectorLayer :return: Hazard classification. :rtype: dict .. versionadded:: 4.0 """

    if not layer.keywords.get('hazard'):
        # return nothing if not hazard layer
        return None

    hazard_classification = None
    # retrieve hazard classification from hazard layer
    for classification in hazard_classes_all:
        classification_name = layer.keywords['classification']
        if classification_name == classification['key']:
            hazard_classification = classification
            break
    return hazard_classification