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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 purposes_for_layer(layer_geometry_key):
 """Get purposes of a layer geometry id. :param layer_geometry_key: The geometry id :type layer_geometry_key: str :returns: List of suitable layer purpose. :rtype: list """

    return_value = []
    for layer_purpose in layer_purposes:
        layer_geometry_keys = [
            i['key'] for i in layer_purpose['allowed_geometries']]
        if layer_geometry_key in layer_geometry_keys:
            return_value.append(layer_purpose['key'])

    return sorted(return_value)