class_docstr: Assign start nodes.
docstr: Assign start nodes to bands.
  
  cur_assigns : dict
      op already assigned.
  
  Returns
  -------
  node_to_bands : dict
      From node to band.
docstr_tok: ["Assign","start","nodes","to","bands",".","cur_assigns",":","dict","op","already","assigned",".","Returns","--","--","--","-","node_to_bands",":","dict","From","node","to","band","."]
code: def assign(
      self, cur_assigns: Dict[str, str] = None
  ) -> Dict[ChunkData, BandType]:
      """
      Assign start nodes to bands.
  
      cur_assigns : dict
          op already assigned.
  
      Returns
      -------
      node_to_bands : dict
          From node to band.
      """
  
imports: from abc import ABC, abstractmethod
  from collections import defaultdict
  from operator import itemgetter
  from typing import List, Dict, Union
  import numpy
  from ....core import ChunkGraph, ChunkData
  from ....core.operand import Operand, Fetch
  from ....lib.ordered_set import OrderedSet
  from ....resource import Resource
  from ....typing import BandType
  from ....utils import implements
label_desc: Use image node_id 2 for calling the AbstractGraphAssigner obj's underlying member method code with example usage: obj.assign(cur_assigns) without return types