import copy


def strip_revision_in_copy(doc_map):
  """ Strip the _rev field in a deep copy of doc_map and return it.
  
  :param dict doc_map: A dict representation of a JSON document.
  :return:  doc_map itself without _rev
  """
  new_doc = copy.deepcopy(doc_map)
  new_doc.pop("_rev", None)
  return new_doc