def tag_search(html_document):
    """
    This function searches all the tags in the html document
    :param html_document:
    :return All the tags as a list:
    """
    tags = []  # tag container
    index = 0
    while index < len(html_document):   # traverse through all the document
        tag = ''
        if html_document[index] == '<' and html_document[index + 1] != '!':  # if it gets tag opening angle bracket
            # and if It is not an html comment(<!)
            while html_document[index] != '>':  # It goes all the way up to '>'
                tag += html_document[index]
                index += 1
            tag += html_document[index]   # append the closing angle bracket
            tags.append(tag)
        else:
            index += 1  # if It can't get an opening angle bracket, It skips it
    return tags