message: Rename _output_stream_adapter to _cc_encrypting_stream, and make static method a function.
diff: @@ -28,6 +28,13 @@ from tink.cc.pybind import tink_bindings
  from tink.util import file_object_adapter
  +@core.use_tink_errors
  +def _new_cc_encrypting_stream(cc_primitive, aad, destination):
  + """Implemented as a separate function to ensure correct error transform."""
  + return tink_bindings.new_cc_encrypting_stream(
  + cc_primitive, aad, destination)
  +
  +
  class RawEncryptingStream(io.RawIOBase):
  """A file-like object which wraps writes to an underlying file-like object.
  @@ -55,23 +62,16 @@ class RawEncryptingStream(io.RawIOBase):
  raise ValueError('ciphertext_destination must be writable')
  cc_ciphertext_destination = file_object_adapter.FileObjectAdapter(
  ciphertext_destination)
  - self._output_stream_adapter = self._get_output_stream_adapter(
  + self._cc_encrypting_stream = _new_cc_encrypting_stream(
  stream_aead, associated_data, cc_ciphertext_destination)
  - @staticmethod
  - @core.use_tink_errors
  - def _get_output_stream_adapter(cc_primitive, aad, destination):
  - """Implemented as a separate method to ensure correct error transform."""
  - return tink_bindings.new_cc_encrypting_stream(
  - cc_primitive, aad, destination)
  -
  @core.use_tink_errors
  - def _write_to_output_stream_adapter(self, b: bytes) -> int:
  - return self._output_stream_adapter.write(bytes(b))
  + def _write_to_cc_encrypting_stream(self, b: bytes) -> int:
  + return self._cc_encrypting_stream.write(bytes(b))
  @core.use_tink_errors
  - def _close_output_stream_adapter(self) -> None:
  - self._output_stream_adapter.close()
  + def _close_cc_encrypting_stream(self) -> None:
  + self._cc_encrypting_stream.close()
  def readinto(self, b: bytearray) -> Optional[int]:
  raise io.UnsupportedOperation()
  @@ -94,7 +94,7 @@ class RawEncryptingStream(io.RawIOBase):
  if not isinstance(b, (bytes, memoryview, bytearray)):
  raise TypeError('a bytes-like object is required, not {}'.format(
  type(b).__name__))
  - written = self._write_to_output_stream_adapter(b)
  + written = self._write_to_cc_encrypting_stream(b)
  if written < 0 or written > len(b):
  raise core.TinkError('Incorrect number of bytes written')
  return written
  @@ -104,7 +104,7 @@ class RawEncryptingStream(io.RawIOBase):
  if self.closed: # pylint:disable=using-constant-test
  return
  self.flush()
  - self._close_output_stream_adapter()
  + self._close_cc_encrypting_stream()
  super(RawEncryptingStream, self).close()
  def writable(self) -> bool:
  