def _update_col_names(x, i):
    """Internal helper function to convert the names of the initial dataset headers

    Keyword Arguments:
        x {string} -- name of the column (can be None)
        i {integer} -- integer representing the number of the column
    Returns:
        string - returns simplified string version of the column.
                 If the column didn't have a name, it return "col_{number of the column}"
    """
    if x != "":
        x = x.replace(" ", "_")
        x = x.replace("-", "_")
        x = x.replace("?", "")
    else:
        x = f"col_{i}"
    return x.lower()