1. package Worlds.Importing is 
  2.  
  3.     -- Raises an exception on error. 
  4.     function Import_World( imagePath, 
  5.                            libName, 
  6.                            domain    : String; 
  7.                            tolerance : Natural ) return A_World; 
  8.     pragma Precondition( imagePath'Length > 0 ); 
  9.     pragma Precondition( libName'Length > 0 ); 
  10.     pragma Precondition( domain'Length > 0 ); 
  11.     pragma Postcondition( Import_World'Result /= null ); 
  12.  
  13. end Worlds.Importing;