def format_line(line):
    """
    Format a line of Matlab into either a markdown line or a code line.

    Parameters
    ----------
    line : str
        The line of code to be formatted. Formatting occurs according to the
        following rules:

        - If the line starts with (at least) two %% signs, a new cell will be
          started.

        - If the line doesn't start with a '%' sign, it is assumed to be legit
          matlab code. We will continue to add to the same cell until reaching
          the next comment line
    """
    if line.startswith('%%'):
        md = True
        new_cell = True
        source = line.split('%%')[1] + '\n'  # line-breaks in md require a line
                                             # gap!

    elif line.startswith('%'):
        md = True
        new_cell = False
        source = line.split('%')[1] + '\n'

    else:
        md = False
        new_cell = False
        source = line


    return new_cell, md, source