code: def modify_collection_metadata(self, collection_uri, metadata, replace=None, name=''):
          
  
          payload = {
                      'collection_metadata': metadata,
                      'name': name
                     }
  
          if replace is not None:
              payload['replace'] = replace
  
          response = self.api_request(collection_uri, method='PUT', data=json.dumps(payload))
  
          return self.__check_success(response)
docs: Modify the metadata for the given collection.
  
          :param collection_uri: The URI that references the collection
          :type collection_uri: String
  
          :param metadata: a dictionary of metadata values to add/modify
          :type metadata: Dict
  
          :rtype: String
          :returns: a message confirming that the metadata is modified
  
          :raises: APIError if the request was not successful