docs: def get_witnesses(self, name='*'):
          """Returns a generator supplying `WitnessText` objects for each work
          in the corpus.
  
          :rtype: `generator` of `WitnessText`
  
          """
          for filepath in glob.glob(os.path.join(self._path, name, '*.txt')):
              if os.path.isfile(filepath):
                  name = os.path.split(os.path.split(filepath)[0])[1]
                  siglum = os.path.splitext(os.path.basename(filepath))[0]
                  yield self.get_witness(name, siglum)