code: def from_json(cls, spec):
      obj = cls(metric=spec["accessor"])
      obj._spec = spec
      return obj
  
file_path: wandb/wandb/apis/reports/_helpers.py
imports: from typing import Optional
  from ..public import PanelMetricsHelper, Run
  from .runset import Runset
  from .util import Attr, Base, Panel, nested_get, nested_set
label_desc: Use image node_id 2 for calling the PCColumn obj's underlying member method code with example usage: obj.from_json(cls, spec) and returns: obj