code: def _get_file_version(self, infile):
          
  
          # Determine file version
          for line1 in infile:
              if line1.strip() != "[Pyspread save file version]":
                  raise ValueError(_("File format unsupported."))
              break
  
          for line2 in infile:
              return line2.strip()
docs: Returns infile version string.