code: def add_data(self, t, msg, vars):
          '''add some data'''
          mtype = msg.get_type()
          for i in range(0, len(self.fields)):
              if mtype not in self.field_types[i]:
                  continue
              f = self.fields[i]
              simple = self.simple_field[i]
              if simple is not None:
                  v = getattr(vars[simple[0]], simple[1])
              else:
                  v = mavutil.evaluate_expression(f, vars)
              if v is None:
                  continue
              if self.xaxis is None:
                  xv = t
              else:
                  xv = mavutil.evaluate_expression(self.xaxis, vars)
                  if xv is None:
                      continue
              try:
                  v_f = float(v)
                  xv_f = float(xv)
              except Exception:
                  continue
              self.y[i].append(v_f)
              self.x[i].append(xv_ff add_data(self, t, msg, vars):
          '''add some data'''
          mtype = msg.get_type()
          for i in range(0, len(self.fields)):
              if mtype not in self.field_types[i]:
                  continue
              f = self.fields[i]
              simple = self.simple_field[i]
              if simple is not None:
                  v = getattr(vars[simple[0]], simple[1])
              else:
                  v = mavutil.evaluate_expression(f, vars)
              if v is None:
                  continue
              if self.xaxis is None:
                  xv = t
              else:
                  xv = mavutil.evaluate_expression(self.xaxis, vars)
                  if xv is None:
                      continue
              try:
                  v_f = float(v)
                  xv_f = float(xv)
              except Exception:
                  continue
              self.y[i].append(v_f)
              self.x[i].append(xv_f)
docs: add some data