code: def add_circle(self,
                     center_lat=None,
                     center_lng=None,
                     radius=None,
                     **kwargs):
          
  
          kwargs.setdefault('center', {})
          if center_lat:
              kwargs['center']['lat'] = center_lat
          if center_lng:
              kwargs['center']['lng'] = center_lng
          if radius:
              kwargs['radius'] = radius
  
          if set(('lat', 'lng')) != set(kwargs['center'].keys()):
              raise AttributeError('circle center coordinates required')
          if 'radius' not in kwargs:
              raise AttributeError('circle radius definition required')
  
          kwargs.setdefault('stroke_color', '#FF0000')
          kwargs.setdefault('stroke_opacity', .8)
          kwargs.setdefault('stroke_weight', 2)
          kwargs.setdefault('fill_color', '#FF0000')
          kwargs.setdefault('fill_opacity', .3)
  
          self.circles.append(kwargs)
docs: Adds a circle dict to the Map.circles attribute
  
          The circle in a sphere is called "spherical cap" and is defined in the
          Google Maps API by at least the center coordinates and its radius, in
          meters. A circle has color and opacity both for the border line and the
          inside area.
  
          It accepts a circle dict representation as well.
  
          Args:
              center_lat (float): The circle center latitude
              center_lng (float): The circle center longitude
              radius  (float): The circle radius, in meters
  
          .. _Circle:
              https://developers.google.com/maps/documen
              tation/javascript/reference#Circle