python def data_process(raw_text_iter: dataset.IterableDataset) -> Tensor:

This is an example of a Python function definition that takes an iterable dataset (`raw_text_iter`) as input and returns a `Tensor` object.

The general syntax of the function definition is as follows:

def function_name(input_argument: input_type) -> output_type:
    """
    Docstring: description of the function
    """
    # Function body
    return output_value

In this case, the function is named `data_process` and takes a single input argument called `raw_text_iter`. The input argument is annotated with the `dataset.IterableDataset` type, indicating the expected type of the argument.

The `-> Tensor` annotation specifies that the function returns a `Tensor` object. The function body, which is not shown here, would contain the code that processes the input data and returns a `Tensor` object.

The docstring is a string literal that describes what the function does, and it is enclosed in triple quotes. It is optional, but it is good practice to include informative docstrings in your code to help others understand how to use your function.