def METHOD_NAME(node, copy_map, field_name='___pyct_anno'):
  """Recursively copies annotations in an AST tree.
  Args:
    node: ast.AST
    copy_map: Dict[Hashable, Hashable], maps a source anno key to a destination
        key. All annotations with the source key will be copied to identical
        annotations with the destination key.
    field_name: str
  """
  for n in gast.walk(node):
    for k in copy_map:
      if hasanno(n, k, field_name):
        setanno(n, copy_map[k], getanno(n, k, field_name), field_name)