def map_id_to_word(integer, tokenizer):
    """
    This methods retuns the english word, which
    corresponse to to given integer. If no
    word exists in the tokenizer the method returns None.

    :param int integer: numerical representation of a word
    :param Tokenizer tokenizer: Tokenizer

    :return str word: word OR None, if no matching word was found
    """
    for word, index in tokenizer.word_index.items():
        if index == integer:
            return word
    return None
