code: def appendStudytoISA(study, pathToISATABFile):
      
      from isatools import isatab
      import os
      try:
          isa = isatab.load(pathToISATABFile, skip_load_tables=True)
          lngth = len(isa.studies)
          base = os.path.basename(study.filename)
          fname = os.path.splitext(base)[0]
          fname = fname + str(lngth)
          ext = os.path.splitext(base)[1]
          fname = fname + ext
          study.filename = fname
          isa.studies.append(study)
          isatab.dump(isa_obj=isa, output_path=pathToISATABFile)
      except FileNotFoundError as err:
          raise err
docs: This function appends a Study object to an ISA file
      Typically, you should use the exploreISA function to check the contents
      of the ISA file!
      :param study: The Study object.
      :type study: ISA Study object
      :param pathToISATABFile: The path to the ISATAB file
      :type pathToISATABFile: string
      :raise FileNotFoundError: If pathToISATABFile does not contain file 'i_Investigation.txt'.