docs: def plot_di(dec=None, inc=None, di_block=None, color='k', marker='o', markersize=20, legend='no', label='', title='', edge='',alpha=1):
      """
      Plot declination, inclination data on an equal area plot.
  
      Before this function is called a plot needs to be initialized with code that looks
      something like:
      >fignum = 1
      >plt.figure(num=fignum,figsize=(10,10),dpi=160)
      >ipmag.plot_net(fignum)
  
      Required Parameters
      -----------
      dec : declination being plotted
      inc : inclination being plotted
  
      or
  
      di_block: a nested list of [dec,inc,1.0]
      (di_block can be provided instead of dec, inc in which case it will be used)
  
      Optional Parameters (defaults are used if not specified)
      -----------
      color : the default color is black. Other colors can be chosen (e.g. 'r')
      marker : the default marker is a circle ('o')
      markersize : default size is 20
      label : the default label is blank ('')
      legend : the default is no legend ('no'). Putting 'yes' will plot a legend.
      edge : marker edge color - if blank, is color of marker
      alpha : opacity
      """
      X_down = []
      X_up = []
      Y_down = []
      Y_up = []
      color_down = []
      color_up = []
  
      if di_block is not None:
          di_lists = unpack_di_block(di_block)
          if len(di_lists) == 3:
              dec, inc, intensity = di_lists
          if len(di_lists) == 2:
              dec, inc = di_lists
      try:
          length = len(dec)
          for n in range(len(dec)):
              XY = pmag.dimap(dec[n], inc[n])
              if inc[n] >= 0:
                  X_down.append(XY[0])
                  Y_down.append(XY[1])
                  if type(color) == list:
                      color_down.append(color[n])
                  else:
                      color_down.append(color)
              else:
                  X_up.append(XY[0])
                  Y_up.append(XY[1])
                  if type(color) == list:
                      color_up.append(color[n])
                  else:
                      color_up.append(color)
      except:
          XY = pmag.dimap(dec, inc)
          if inc >= 0:
              X_down.append(XY[0])
              Y_down.append(XY[1])
              color_down.append(color)
          else:
              X_up.append(XY[0])
              Y_up.append(XY[1])
              color_up.append(color)
  
      if len(X_up) > 0:
          plt.scatter(X_up, Y_up, facecolors='none', edgecolors=color_up,
                      s=markersize, marker=marker, label=label,alpha=alpha)
  
      if len(X_down) > 0:
          plt.scatter(X_down, Y_down, facecolors=color_down, edgecolors=edge,
                      s=markersize, marker=marker, label=label,alpha=alpha)
      if legend == 'yes':
          plt.legend(loc=2)
      plt.tight_layout()
      if title != "":
          plt.title(title)