class_docstr: Context of converter
  
  This context shares names during exporting.
  
  Attributes:
      name_list (dict): list of being exported as ONNX node name with pinned
          or not, keyed by instance ID. When the target variable is
          ``chainer.Variable`` or ``chainer.Parameter``, instance ID of
          ``ndarray`` held by the variable is also put as key, because some
          functions like ``F.where`` internally unwrap variable.
class_docstr_tok: ["Context","of","converter","This","context","shares","names","during","exporting",".","Attributes",":","name_list","(","dict",")",":","list","of","being","exported","as","ONNX","node","name","with","pinned","or","not",",","keyed","by","instance","ID",".","When","the","target","variable","is","``","chainer.Variable","``","or","``","chainer.Parameter","``",",","instance","ID","of","``","ndarray","``","held","by","the","variable","is","also","put","as","key",",","because","some","functions","like","``","F.where","``","internally","unwrap","variable","."]
code: def is_pinned(self, variable):
      str_id = id(variable)
      if str_id not in self.name_list:
          return False
      return self.name_list[str_id][1]
  
file_path: chainer/onnx_chainer/context.py
imports: import chainer
  import onnx
  from onnx import numpy_helper
  from onnx_chainer import onnx_helper
label_desc: Use image node_id 4 for calling the Context obj's underlying member method code with example usage: obj.is_pinned(variable) and returns: self, False