code: def _recursive_dict_update(dict_, other, **kwargs):
      
      overwrite = kwargs['overwrite']
  
      for key, other_value in iteritems(other):
          if key in dict_:
              value = dict_[key]
              if is_mapping(value) and is_mapping(other_value):
                  _recursive_dict_update(value, other_value, overwrite=overwrite)
                  continue
          if overwrite:
              dict_[key] = other_value
          else:
              dict_.setdefault(key, other_value)
docs: Deep/recursive version of ``dict.update``.
  
      If a key is present in both dictionaries, and points to
      "child" dictionaries, those will be appropriately merged.
  
      :param overwrite: Whether to overwrite exisiting dictionary values