class_docstr: Basic topological (non-weighted) directed Graph class
  
  Member variables:
  
  * V (int > 0): the number of vertices
  * E (int >= 0): the number of edges
  
  Properties:
  
  * vertices (list, type=int, shape=(V,))  vertices id
  * edges (list, type=int, shape=(E,2)): edges as vertices id tuples
class_docstr_tok: ["Basic","topological","(","non-weighted",")","directed","Graph","class","Member","variables",":","*","V","(","int",">","0",")",":","the","number","of","vertices","*","E","(","int",">","=","0",")",":","the","number","of","edges","Properties",":","*","vertices","(","list",",","type=int",",","shape=","(","V",",",")",")","vertices","id","*","edges","(","list",",","type=int",",","shape=","(","E,2",")",")",":","edges","as","vertices","id","tuples"]
docstr: To get the graph's vertices (as id)
          
docstr_tok: ["To","get","the","graph","'s","vertices","(","as","id",")"]
code: def get_vertices(self):
      """To get the graph's vertices (as id)"""
      return self.vertices
  
imports: import numpy
  from scipy.sparse import coo_matrix
label_desc: Use image node_id 2 for calling the Graph obj's underlying member method code with example usage: obj.get_vertices() and returns: self