def get_cell_description(cell_input):
    """Gets cell description

    Cell description is the first line of a cell,
    in one of this formats:

    * single line docstring
    * single line comment
    * function definition
    """
    try:
        first_line = cell_input.split("\n")[0]
        if first_line.startswith(('"', '#', 'def')):
            return first_line.replace('"','').replace("#",'').replace('def ', '').replace("_", " ").strip()
    except:
        pass
    return "no description"