code: def find_missing_keys(self):
      missing = [
          k
          for k in self.schema.keys()
          if k not in self and not self.has_default(k)
      ]
      placeholders = [
          k for k in self if self[k] in ("<missing>", "<value>")
      ]
      return missing + placeholders
  
imports: from __future__ import absolute_import
  from __future__ import print_function
  from __future__ import division
  import inspect
  import importlib
  import re
label_desc: Use image node_id 11 for calling the SchemaDict obj's underlying member method code with example usage: obj.find_missing_keys() and returns: unknown