text: #pragma once
  
  #include <list>
  
  #include "identification.h"
  
  namespace depkit {
  // `requirement` in BNF
  class Requirement {
  public:
    Requirement() {}
    Requirement(IdentificationPtr &req) : requirement_(req) {}
  
  public:
    IdentificationPtr requirement_;
  };
  using RequirementPtr = std::shared_ptr<Requirement>;
  } // namespace depkit
  