class_docstr: Polygon class for data handling
  
  Parameters
  ----------
  vertices : (Nv, 3) array
      Vertex coordinates. If faces is not specified, then this will instead
      be interpreted as (Nf, 3, 3) array of coordinates.
  edges : (Nv, 2) array
      Constraining edges specified by vertex indices.
  faces : (Nf, 3) array
      Indexes into the vertex array.
  
  Notes
  -----
  All arguments are optional.
docstr: Return an array (Nv, 2) of vertex indices.
  
  If no vertices or faces are specified, the function returns None.
docstr_tok: ["Return","an","array","(","Nv",",","2",")","of","vertex","indices",".","If","no","vertices","or","faces","are","specified",",","the","function","returns","None","."]
code: def edges(self):
      """Return an array (Nv, 2) of vertex indices.
  
      If no vertices or faces are specified, the function returns None.
      """
      return self._edges
  
file_path: vispy/vispy/geometry/polygon.py
imports: import numpy
  from .triangulation import Triangulation
label_desc: Use image node_id 6 for calling the PolygonData obj's underlying member method code with example usage: obj.edges() and returns: self