class_docstr: Object representing a complex data producer.
class_docstr_tok: ["Object","representing","a","complex","data","producer","."]
code: def _update_line_data(self, count):
      self._line_data[:, 1] = np.roll(self._line_data[:, 1], -1)
      self._line_data[-1, 1] = abs(
          sin((count / self._num_iters) * 16 * pi)
      )
      return self._line_data
  
imports: import time
  from math import sin, pi
  import numpy
  from PyQt5 import QtWidgets, QtCore
  from vispy.scene import SceneCanvas, visuals
  from vispy.app import use_app, Timer
label_desc: Use image node_id 4 for calling the DataSource obj's underlying member method code with example usage: obj._update_line_data(count) and returns: self