Storage: download_as_string documentation says that it downloads a string, instead of bytes

[olsgaard]

For google-cloud-storage, in the documentation for download_as_string() method on blobs, it says on line 715:

    """Download the contents of this blob as a string.

This is not true. The confusingly named method downloads the content as bytes, not string.

On line 731, the return type is correctly declared as bytes, but reading the documentation, you are still presented with conflicting information.

[HemangChothani]

@tseaver is it ok to change method's name ,Please suggest.

[tseaver]

@HemangChothani We cannot change the method's name: that would be a breaking change. Note that we chose that method name explicitly for compatibility with the API of the AWS / S3 boto library.

We can update its docstring to indicate its actual semantics.