code: def get_brain(brain_or_object):
      
      if is_brain(brain_or_object):
          return brain_or_object
      if is_root(brain_or_object):
          return brain_or_object
  
      # fetch the brain by UID
      uid = get_uid(brain_or_object)
      uc = get_tool("uid_catalog")
      results = uc({"UID": uid}) or search(query={'UID': uid})
      if len(results) == 0:
          return None
      if len(results) > 1:
          fail(500, "More than one object with UID={} found in portal_catalog".format(uid))
      return results[0]
docs: Return a ZCatalog brain for the object
  
      :param brain_or_object: A single catalog brain or content object
      :type brain_or_object: ATContentType/DexterityContentType/CatalogBrain
      :returns: True if the object is a catalog brain
      :rtype: bool