code: def test_clear():
      y = list(np.random.normal(size=100))
      x = np.linspace(5, 10, 100)
      pdi = pg.PlotDataItem(x, y)
      pdi.clear()
  
      assert pdi.xData is None
      assert pdi.yData is None
  
file_path: pyqtgraph/tests/graphicsItems/test_PlotDataItem.py
imports: import warnings
  import numpy
  import pyqtgraph
  from pyqtgraph.Qt import QtGui
label_desc: Use image node_id 7 for calling a global function with example usage: test_clear() without return types