docs: def write_collection_info(self, collection: BioCCollection):
          """
          Writes the collection information: encoding, version, DTD, source, date, key, infons, etc.
          """
          elem = etree.Element('source')
          elem.text = collection.source
          self.__writer.send(elem)
  
          elem = etree.Element('date')
          elem.text = collection.date
          self.__writer.send(elem)
  
          elem = etree.Element('key')
          elem.text = collection.key
          self.__writer.send(elem)
  
          for k, v in collection.infons.items():
              elem = etree.Element('infon', {'key': str(k)})
              elem.text = str(v)
              self.__writer.send(elem)