def fsearch(f, s):
    """
    Search for a line in a file.

    Parameters
    ----------
    f : file_like
        File_like object to search in.
    s : string
        String to search for.

    Returns
    -------
    line : string or None
        The first line that contains the string. None if not found.
    p : integer or None
        The position where `s` begins in `line`. None if not found.

    Notes
    -----
    The search begins at the current file position.
    """
    for line in f:
        p = line.find(s)
        if p > -1:
            return line, p
    return None, None