Take a list of dictionaries, and tokenize/normalize.

def normalize_params(params):
    """Take a list of dictionaries, and tokenize/normalize."""
    # Collect a set of all fields
    fields = set()
    for p in params:
        fields.update(p)
    fields = sorted(fields)

    params2 = list(pluck(fields, params, MISSING))
    # Non-basic types (including MISSING) are unique to their id
    tokens = [
        tuple(x if isinstance(x, (int, float, str)) else id(x) for x in p)
        for p in params2
    ]

    return fields, tokens, params2