          keys = list(self.calcs.stats.keys())
  
          for idx, item in enumerate(self.lines_sort(keys)):
              if initiate:
                  self.lines.extend(self.ax1.plot(xrng, self.calcs.stats[item[0]],
                                                  label=item[1], linewidth=item[2], color=item[3]))
              else:
                  self.lines[idx].set_data(xrng, self.calcs.stats[item[0]])
  
          if initiate:
              self.legend_place()
 
</s> remove         for idx, item in enumerate(self.lines_sort(keys)):
 </s> add         for idx, item in enumerate(self._lines_sort(keys)): </s> remove         keys = list(self.calcs.stats.keys())
 </s> add         keys = list(self._calcs.stats.keys()) </s> remove                 self.lines[idx].set_data(xrng, self.calcs.stats[item[0]])
 </s> add                 self._lines[idx].set_data(xrng, self._calcs.stats[item[0]]) </s> remove             xrng = list(range(self.calcs.iterations))
 </s> add             xrng = list(range(self._calcs.iterations)) </s> remove             self.legend_place()
 </s> add             self._legend_place()
                self._lines.extend(self._ax1.plot(xrng, self._calcs.stats[item[0]],
                                                  label=item[1], linewidth=item[2], color=item[3]))
          keys = list(self.calcs.stats.keys())
  
          for idx, item in enumerate(self.lines_sort(keys)):
              if initiate:
                self._lines.extend(self._ax1.plot(xrng, self._calcs.stats[item[0]],
                                                  label=item[1], linewidth=item[2], color=item[3]))
                self._lines.extend(self._ax1.plot(xrng, self._calcs.stats[item[0]],
                                                  label=item[1], linewidth=item[2], color=item[3]))
              else:
                  self.lines[idx].set_data(xrng, self.calcs.stats[item[0]])
  
          if initiate:
              self.legend_place()
keep keep keep keep replace replace keep keep keep keep keep
 Update matplotlib requirement
  - bump min requirement to 3.5.1
  - Fix custom toolbar for v3.5.1
  - Documentation + linting 
lib/gui/display_graph.py