// new gdcmFile if the user changes the list). ExecuteData would then use
// those gdcmFile and hence avoid calling the construtor:
// - advantage: the header of the files would only be parser once.
// - drawback: once execute information is called (i.e. on creation of
// new gdcmFile if the user changes the list). ExecuteData would then use
// those gdcmFile and hence avoid calling the construtor:
// - advantage: the header of the files would only be parser once.
// - drawback: once execute information is called (i.e. on creation of