class_docstr: Radar chart created from a pandas Dataframe. Each column of the df will be
  represented as a loop in the radar chart. Each row of the df will be
  represented as a spoke of the radar chart
  
  Attributes
  ----------
  data: DataFrame
      data for the radar
  band_type: {"circle", "polygon"} (default: "circle")
      type of bands to display in the radar
  num_bands: Int (default: 5)
      number of bands on the radar. As of now, this attribute is not
      dynamic and it has to set in the constructor
  data_range: List (default: [0, 1])
      range of data
  fill: Bool(default: True)
      flag which lets us fill the radar loops or not
code: def update_fill(self, *args):
      if self.fill:
          with self.loops.hold_sync():
              self.loops.fill = "inside"
              self.loops.fill_opacities = [0.2] * len(self.loops.y)
      else:
          self.loops.fill = "none"
          self.loops.fill_opacities = [0.0] * len(self.loops.y)
  
file_path: bqplot/bqplot/plotting_widgets.py
imports: from ipywidgets import Layout
  from traitlets import List, Enum, Int, Bool
  from traittypes import DataFrame
  from bqplot import Figure, LinearScale, Lines, Label
  from bqplot.marks import CATEGORY10
  import numpy
label_desc: Use image node_id 4 for calling the Radar obj's underlying member method code with example usage: obj.update_fill() without return types