docs: def inputfile(self, inputtemplate=None):
          """Return the inputfile for the specified inputtemplate, if ``inputtemplate=None``, inputfile is returned regardless of inputtemplate. This function may only return 1 and returns an error when multiple input files can be returned, use ``inputfiles()`` instead."""
          inputfiles = list(self.inputfiles(inputtemplate))
          if len(inputfiles) < 1:
              raise Exception("No such input file")
          elif len(inputfiles) > 1:
              raise Exception("Multiple input files matched. Use inputfiles() instead!")
          return inputfiles[0]