


'''simple docstring'''
import os
from distutils.util import strtobool


def       _lowercase							(					UpperCamelCase__							:       Optional[Any],					UpperCamelCase__							:       str      ):
 for e in env_keys:
  __A	:		List[Any]	  =      int(os.environ.get(UpperCamelCase__,					-1      )      )
  if val >= 0:
   return val
 return default


def       _lowercase							(					UpperCamelCase__							:       Optional[int],					UpperCamelCase__							:       Any=False      ):
 __A	:		List[Any]	  =      os.environ.get(UpperCamelCase__,					str(UpperCamelCase__      )      )
 return strtobool(UpperCamelCase__      ) == 1  # As its name indicates `strtobool` actually returns an int...


def       _lowercase							(					UpperCamelCase__							:       Dict,					UpperCamelCase__							:       Optional[int]="no"      ):
 __A	:		Optional[int]	  =      os.environ.get(UpperCamelCase__,					str(UpperCamelCase__      )      )
 return value










'''simple docstring'''
def       _lowercase							(					UpperCamelCase__							:       dict      ):
 __A	:		Dict	  =      set()
 # edges = list of graph's edges
 __A	:		Any	  =      get_edges(UpperCamelCase__      )

 # While there are still elements in edges list, take an arbitrary edge
 # (from_node, to_node) and add his extremity to chosen_vertices and then
 # remove all arcs adjacent to the from_node and to_node
 while edges:
  __A  ,__A	:		List[Any]	  =      edges.pop()
  chosen_vertices.add(UpperCamelCase__      )
  chosen_vertices.add(UpperCamelCase__      )
  for edge in edges.copy():
   if from_node in edge or to_node in edge:
    edges.discard(UpperCamelCase__      )
 return chosen_vertices


def       _lowercase							(					UpperCamelCase__							:       dict      ):
 __A	:		Any	  =      set()
 for from_node, to_nodes in graph.items():
  for to_node in to_nodes:
   edges.add((from_node, to_node)      )
 return edges


if __name__ == "__main__":
 import doctest

 doctest.testmod()

 # graph = {0: [1, 3], 1: [0, 3], 2: [0, 3, 4], 3: [0, 1, 2], 4: [2, 3]}
 # print(f"Matching vertex cover:\n{matching_min_vertex_cover(graph)}")






