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))
      )
  
file_path: catboost/contrib/python/plotly/py3/plotly/figure_factory/_ternary_contour.py
imports: import plotly.colors
  from plotly.graph_objs import graph_objs
  from plotly import exceptions
  from plotly import optional_imports
  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