code: def _get_writable_metadata(self):
          
          # NOTE: This assumes `self.name` is unicode.
          object_metadata = {"name": self.name}
          for key in self._changes:
              if key in _WRITABLE_FIELDS:
                  object_metadata[key] = self._properties[key]
  
          return object_metadata
docs: Get the object / blob metadata which is writable.
  
          This is intended to be used when creating a new object / blob.
  
          See the `API reference docs`_ for more information, the fields
          marked as writable are:
  
          * ``acl``
          * ``cacheControl``
          * ``contentDisposition``
          * ``contentEncoding``
          * ``contentLanguage``
          * ``contentType``
          * ``crc32c``
          * ``md5Hash``
          * ``metadata``
          * ``name``
          * ``storageClass``
  
          For now, we don't support ``acl``, access control lists should be
          managed directly through :class:`ObjectACL` methods.