docs: def get_document(self, index=0):
          """ Return the metadata for the specified document, as a
          Document object
  
          :type index: int
          :param index: the index of the document
  
          :rtype: Document
          :returns: the metadata for the specified document
  
  
          """
          try:
              return Document(self.metadata()['alveo:documents'][index], self.client)
          except IndexError:
              raise ValueError('No document exists for this item with index: '
                               + str(index))