- layer = layer.lower()
- suffix_dict = {"l2": "eth",
- "l3_ip4": "ipv4",
- "l3_ip6": "ipv6"
- }
- if layer == "l4":
- raise NotImplementedError
- try:
- suffix = suffix_dict[layer]
- except KeyError:
- raise ValueError("Unexpected value of layer argument {0}."
- "Valid options are: {1}"
- .format(layer, suffix_dict.keys()))