def _DrawHours(self):
    """Generates svg to show a vertical hour and sub-hour grid

    Returns:
      # A string containing a polyline tag for each grid line
      " <polyline class="FullHour" points="20,0 ..."
    """
    tmpstrs = []
    for i in range(0, self._gwidth, self._min_grid):
      if i % self._hour_grid == 0:
        tmpstrs.append('<polyline class="FullHour" points="%d,%d, %d,%d" />' \
                       % (i + .5 + 20, 20, i + .5 + 20, self._gheight))
        tmpstrs.append('<text class="Label" x="%d" y="%d">%d</text>'
                       % (i + 20, 20,
                         (i / self._hour_grid + self._offset) % 24))
      else:
        tmpstrs.append('<polyline class="SubHour" points="%d,%d,%d,%d" />' \
                       % (i + .5 + 20, 20, i + .5 + 20, self._gheight))
    return "".join(tmpstrs)
dataset/ETHPy150Open google/transitfeed/gtfsscheduleviewer/marey_graph.py/MareyGraph._DrawHours/original