docs: def applySiiQcValidation(siiContainer, specfile):
      """Iterates over all Sii entries of a specfile in siiContainer and validates
      if they surpass a user defined quality threshold. The parameters for
      validation are defined in ``siiContainer.info[specfile]``:
  
          - ``qcAttr``, ``qcCutoff`` and ``qcLargerBetter``
  
      In addition to passing this validation a ``Sii`` has also to be at the first
      list position in the ``siiContainer.container``. If both criteria are met
      the attribute ``Sii.isValid`` is set to ``True``.
  
      :param siiContainer: instance of :class:`maspy.core.SiiContainer`
      :param specfile: unambiguous identifier of a ms-run file. Is also used as
          a reference to other MasPy file containers.
      """
      attr = siiContainer.info[specfile]['qcAttr']
      cutOff = siiContainer.info[specfile]['qcCutoff']
      if siiContainer.info[specfile]['qcLargerBetter']:
          evaluator = lambda sii: getattr(sii, attr) >= cutOff and sii.rank == 1
      else:
          evaluator = lambda sii: getattr(sii, attr) <= cutOff and sii.rank == 1
  
      for itemList in listvalues(siiContainer.container[specfile]):
          #Set the .isValid attribute of all Sii to False
          for sii in itemList:
              sii.isValid = False
  
          #Validate the first Sii
          sii = itemList[0]
          if evaluator(sii):
              sii.isValid = True