class_docstr: The workspace contains the processing information and state for
  a pipeline run on an image set
class_docstr_tok: ["The","workspace","contains","the","processing","information","and","state","for","a","pipeline","run","on","an","image","set"]
docstr: Initialize the grids for an image set
  
  last - none if first in image set or the return value from
         this method.
  returns a grid dictionary
code: def set_grids(self, last=None):
      """Initialize the grids for an image set
  
      last - none if first in image set or the return value from
             this method.
      returns a grid dictionary
      """
      if last is None:
          last = {}
      self.__grid = last
      return self.__grid
  
imports: import io
  import logging
  import os
  import h5py
  import cellprofiler_core.utilities.measurement
  from ._disposition_changed_event import DispositionChangedEvent
  from ..constants.measurement import EXPERIMENT
  from ..constants.workspace import DISPOSITION_CONTINUE
  from ..utilities.hdf5_dict import HDF5FileList
label_desc: Use image node_id 15 for calling the Workspace obj's underlying member method code with example usage: obj.set_grids(last) and returns: self