code: def all_input(self):
          
          return {'INCAR': self.incar,
                  'KPOINTS': self.kpoints,
                  'POSCAR': self.poscar,
                  'POTCAR': self.potcar}
docs: Returns all input files as a dict of {filename: vasp object}
  
          Returns:
              dict of {filename: object}, e.g., {'INCAR': Incar object, ...}