docs: def has_wrap_around_links(self, minimum_working=0.9):
          """Test if a machine has wrap-around connections installed.
  
          Since the Machine object does not explicitly define whether a machine
          has wrap-around links they must be tested for directly. This test
          performs a "fuzzy" test on the number of wrap-around links which are
          working to determine if wrap-around links are really present.
  
          Parameters
          ----------
          minimum_working : 0.0 <= float <= 1.0
              The minimum proportion of all wrap-around links which must be
              working for this function to return True.
  
          Returns
          -------
          bool
              True if the system has wrap-around links, False if not.
          """
          working = 0
          for x in range(self.width):
              if (x, 0, Links.south) in self:
                  working += 1
              if (x, self.height - 1, Links.north) in self:
                  working += 1
              if (x, 0, Links.south_west) in self:
                  working += 1
              if (x, self.height - 1, Links.north_east) in self:
                  working += 1
  
          for y in range(self.height):
              if (0, y, Links.west) in self:
                  working += 1
              if (self.width - 1, y, Links.east) in self:
                  working += 1
  
              # Don't re-count links counted when scanning the x-axis
              if y != 0 and (0, y, Links.south_west) in self:
                  working += 1
              if (y != self.height - 1 and
                      (self.width - 1, y, Links.north_east) in self):
                  working += 1
  
          total = (4 * self.width) + (4 * self.height) - 2
  
          return (float(working) / float(total)) >= minimum_working