foo.cc: In member function 'Time Time::operator-(int)':
foo.cc:43:5: warning: no return statement in function returning non-void [-Wreturn-type]
   43 |     }
      |     ^
foo.cc: In member function 'int Time::operator-(Time&)':
foo.cc:47:5: warning: no return statement in function returning non-void [-Wreturn-type]
   47 |     }
      |     ^

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