import textwrap


def format_description(description, line_width=50, num_lines=3):
    """Formats the description field

    Description field can be long. This function line wraps to a specified number
    of lines. The last line trails with ".." if the text still overflows to
    signal that there is more.
    """
    if not description:
        return ''
    lines = textwrap.wrap(description)
    lines = lines[:num_lines]
    last_line = lines.pop()

    if len(last_line) > line_width and line_width > 2:
        last_line = "{0}..".format(last_line[:-2])

    lines.append(last_line)
    return "\n".join(lines)