code: def date(self, value=None):
          
          if not (value is None):
              if (self.metadatatype == "native"):
                  self.metadata['date'] = value
              else:
                  self._date = value
          if (self.metadatatype == "native"):
              if 'date' in self.metadata:
                  return self.metadata['date']
              else:
                  return None
          else:
              return self._date
docs: Get or set the document's date from/in the metadata.
  
             No arguments: Get the document's date from metadata
             Argument: Set the document's date in metadata