text: #include <ostream>
  
  #include "directionality.hpp"
  
  namespace g {
  std::ostream& operator<<(std::ostream& os, Directionality d)
  {
    switch (d) {
    case Directionality::Directed: os << "Directed"; break;
    case Directionality::Undirected: os << "Undirected"; break;
    }
  
    return os;
  }
  } // namespace g
  