docs: def plot_poles_colorbar(map_axis, plons, plats, A95s, colorvalues, vmin, vmax,
                          colormap='viridis', edgecolor='k', marker='o', markersize='20',
                          alpha=1.0, colorbar=True, colorbar_label='pole age (Ma)'):
      """
      This function plots multiple paleomagnetic pole and A95 error ellipse on a cartopy map axis.
      The poles are colored by the defined colormap.
  
      Before this function is called, a plot needs to be initialized with code
      such as that in the make_orthographic_map function.
  
      Example
      -------
      >>> plons = [200, 180, 210]
      >>> plats = [60, 40, 35]
      >>> A95s = [6, 3, 10]
      >>> ages = [100,200,300]
      >>> vmin = 0
      >>> vmax = 300
      >>> map_axis = ipmag.make_orthographic_map(central_longitude=200, central_latitude=30)
      >>> ipmag.plot_poles_colorbar(map_axis, plons, plats, A95s, ages, vmin, vmax)
  
      Required Parameters
      -----------
      map_axis : the name of the current map axis that has been developed using cartopy
      plons : the longitude of the paleomagnetic pole being plotted (in degrees E)
      plats : the latitude of the paleomagnetic pole being plotted (in degrees)
      A95s : the A_95 confidence ellipse of the paleomagnetic pole (in degrees)
      colorvalues : what attribute is being used to determine the colors
      vmin : what is the minimum range for the colormap
      vmax : what is the maximum range for the colormap
  
      Optional Parameters (defaults are used if not specified)
      -----------
      colormap : the colormap used (default is 'viridis'; others should be put as a string with quotes, e.g. 'plasma')
      edgecolor : the color desired for the symbol outline
      marker : the marker shape desired for the pole mean symbol (default is 'o' aka a circle)
      colorbar : the default is to include a colorbar (True). Putting False will make it so no legend is plotted.
      colorbar_label : label for the colorbar
      """
  
      if not has_cartopy:
          print('-W- cartopy must be installed to run ipmag.plot_poles_colorbar')
          return
  
      color_mapping = plt.cm.ScalarMappable(cmap=colormap, norm=plt.Normalize(vmin=vmin, vmax=vmax))
      colors = color_mapping.to_rgba(colorvalues).tolist()
  
      plot_poles(map_axis, plons, plats, A95s,
                       label='', color=colors, edgecolor=edgecolor, marker=marker)
  
      if colorbar == True:
          sm = plt.cm.ScalarMappable(
              cmap=colormap, norm=plt.Normalize(vmin=vmin, vmax=vmax))
          sm._A = []
          plt.colorbar(sm, orientation='horizontal', shrink=0.8,
                       pad=0.05, label=colorbar_label)