The commands shown in the commands on the page yield errors.

[SurferJeffAtGoogle]

https://googlecloudplatform.github.io/google-cloud-python/latest/language/usage.html

[udasahai]

document = language.types.Document( content = 'I am going from las vegas to los Angeles', type=language.enums.Type.PLAIN_TEXT,)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'Type'

[lukesneeringer]

Sure enough. It is language.enums.Document.Type.PLAIN_TEXT.