Reads data from a file and passes it as an argument to the function.

read_data_from_file.py

def read_data_from_file(filename, data_arg):
    """
    Reads the data from a file and passes it into the
    function as the kwarg defined in the data_arg parameter.
    :param filename: The filename to read the data from.
    :param data_arg: The argument to pass in the data as.
    :return: A new with the data already passed in.
    """

    def readfile_decorator(input_func):
        def new_func(*args, **kwargs):
            with open(filename) as f:
                data = (json.loads(x) for x in f)
                kwargs[data_arg] = data
                return input_func(*args, **kwargs)

        return new_func

    return readfile_decorator