code: def load(self, filename):
          '''load points from a file.
          returns number of points loaded'''
          f = open(filename, mode='r')
          self.clear()
          for line in f:
              if line.startswith('#'):
                  continue
              line = line.strip()
              if not line:
                  continue
              a = line.split()
              if len(a) != 2:
                  raise MAVFenceError("invalid fence point line: %s" % line)
              self.add_latlon(float(a[0]), float(a[1]))
          f.close()
          return len(self.pointsf load(self, filename):
          '''load points from a file.
          returns number of points loaded'''
          f = open(filename, mode='r')
          self.clear()
          for line in f:
              if line.startswith('#'):
                  continue
              line = line.strip()
              if not line:
                  continue
              a = line.split()
              if len(a) != 2:
                  raise MAVFenceError("invalid fence point line: %s" % line)
              self.add_latlon(float(a[0]), float(a[1]))
          f.close()
          return len(self.points)
docs: load points from a file.
          returns number of points loaded