code: def _make_nodes(self, dsk_graph, array, iteration_order, masked,
                      top=False):
          
          cache_key = _array_id(array, iteration_order, masked)
          # By the end of this function Nodes will be a dictionary with one item
          # per chunk to be processed for this array.
          nodes = self._node_cache.get(cache_key, None)
  
          if nodes is None:
              if hasattr(array, 'streams_handler'):
                  nodes = self._make_stream_handler_nodes(dsk_graph, array,
                                                          iteration_order,
                                                          masked)
              else:
                  nodes = {}
                  chunks = []
  
                  name = '{}\n{}'.format(array.__class__.__name__, array.shape)
                  biggus_chunk_func = self.lazy_chunk_creator(name)
  
                  chunk_index_gen = biggus._init.ProducerNode.chunk_index_gen
                  for chunk_key in chunk_index_gen(array.shape,
                                                   iteration_order[::-1]):
                      biggus_array = array[chunk_key]
                      pretty_key = ', '.join(map(slice_repr, chunk_key))
                      chunk_id = ('chunk shape: {}\nsource key: [{}]\n\n{}'
                                  ''.format(biggus_array.shape, pretty_key,
                                            uuid.uuid4()))
                      task = (biggus_chunk_func, chunk_key, biggus_array, masked)
                      chunks.append(task)
                      assert chunk_id not in dsk_graph
                      dsk_graph[chunk_id] = task
                      nodes[chunk_id] = task
              self._node_cache[cache_key] = nodes
          return nodes
docs: Recursive function that returns the dask items for the given array.
  
          NOTE: Currently assuming that all tasks are a tuple, with the second
          item being the keys used to index the source of the respective input
          array.