from typing import Sequence


def html_open(style: Sequence[str]) -> str:
    """
    HTML tags to open a style.

    :param style: sequence of html tags without the '<' and '>'
    :return: opening html tags joined into a single string

    >>> style = ['font color="red" size="32"', 'b', 'i', 'u']
    >>> html_open(style)
    '<font color="red" size="32"><b><i><u>'
    """
    return "".join((f"<{x}>" for x in style))