code: def _get_sub_prop(container, keys, default=None):
      
      sub_val = container
      for key in keys:
          if key not in sub_val:
              return default
          sub_val = sub_val[key]
      return sub_val
docs: Get a nested value from a dictionary.
  
      This method works like ``dict.get(key)``, but for nested values.
  
      Arguments:
          container (dict):
              A dictionary which may contain other dictionaries as values.
          keys (iterable):
              A sequence of keys to attempt to get the value for. Each item in
              the sequence represents a deeper nesting. The first key is for
              the top level. If there is a dictionary there, the second key
              attempts to get the value within that, and so on.
          default (object):
              (Optional) Value to returned if any of the keys are not found.
              Defaults to ``None``.
  
      Examples:
          Get a top-level value (equivalent to ``container.get('key')``).
  
          >>> _get_sub_prop({'key': 'value'}, ['key'])
          'value'
  
          Get a top-level value, providing a default (equivalent to
          ``container.get('key', default='default')``).
  
          >>> _get_sub_prop({'nothere': 123}, ['key'], default='not found')
          'not found'
  
          Get a nested value.
  
          >>> _get_sub_prop({'key': {'subkey': 'value'}}, ['key', 'subkey'])
          'value'
  
      Returns:
          object: The value if present or the default.