def convert_type(data):
    """
    This function converts each categorical feature with a numerical
    data type to a string data type.

    Parameters:
    data: The dataset in question.

    Returns:
    data: The transformed dataset.
    """
#   Categorical features
    columns = ['Browser', 'OperatingSystems', 'Region', 'TrafficType']
    for col in columns:
        data[col] = data[col].apply(lambda x: str(x))
    return data