def guess_mimi_type(body: str):
    """
        This method guesses the content type of the body.
        It uses the first part of the content type.
        For example, if the content type is "<!DOCTYPE html>",
        it will return "text/html".
        else
        it will return "text/plain".

        Parameters
        ----------
        body : `str`
            The body of the request.
    """
    if body is None:
        return 'text/plain'
    
    if body.startswith(("<!DOCTYPE html>", "<!doctype html>", "<html>")):
        return "text/html"
    else:
        return "text/plain"