docs: def merge(self, path, outfile, infiles):
          """Merge files
          """
          with open(path + outfile, 'w') as out_f:
              for i in infiles:
                  if os.path.isfile("{0}{1}".format(path, i)):
                      with open(path + i, "r") as in_f:
                          for line in in_f:
                              out_f.write(line)