#ifndef keyset_h#define keyset_h#include <object.h>#include <mit/rca/meta/hash-tab.h>class KeySet ;class KeySet : public HashTab { public:  KeySet();  ~KeySet();  command(int argc, const char*const* argv);  void Union(KeySet *set2);  int Numelements() const { return elements_ ; }  inline int Emptyset() {     if (elements_ == 0)       return 1 ;     return 0;  };  KeySet *Copy();  int Subset(KeySet *set);  void Intersection(KeySet *set2);  void Subtract(KeySet *set1);  int Eq(KeySet *set1);  inline int Neq(KeySet *y)     {       if (Eq(y) == 1) 	return 0;       return 1; }  void Pp(char *desc = NULL);  void Add(char *key, char *element = NULL);  char *SetToList();  int Member(char *key);};#endif