code: def _polygon_area(x, y):
      return 0.5 * np.abs(
          np.dot(x, np.roll(y, 1)) - np.dot(y, np.roll(x, 1))
      )
  
imports: from __future__ import absolute_import
  import plotly.colors
  from plotly.graph_objs import graph_objs
  from plotly import exceptions, optional_imports
  from plotly import optional_imports
  from plotly.graph_objs import graph_objs
  from skimage import measure
label_desc: Use image node_id 8 for calling a global function with example usage: _polygon_area(x, y) and returns: unknown