code: def dropNonJournals(self, ptVal = 'J', dropBad = True, invert = False):
          
          if dropBad:
              self.dropBadEntries()
          if invert:
              self._collection = {r for r in self._collection if r['pubType'] != ptVal.upper()}
          else:
              self._collection = {r for r in self._collection if r['pubType'] == ptVal.upper()}
docs: Drops the non journal type `Records` from the collection, this is done by checking _ptVal_ against the PT tag
  
          # Parameters
  
          _ptVal_ : `optional [str]`
  
          > Default `'J'`, The value of the PT tag to be kept, default is `'J'` the journal tag, other tags can be substituted.
  
          _dropBad_ : `optional [bool]`
  
          > Default `True`, if `True` bad `Records` will be dropped as well those that are not journal entries
  
          _invert_ : `optional [bool]`
  
          > Default `False`, Set `True` to drop journals (or the PT tag given by _ptVal_) instead of keeping them. **Note**, it still drops bad Records if _dropBad_ is `True`