make /official a Python module

[yhliang2018]

make /official as a Python module to unify import of utils

[robieta]

Fundamentally I think the fact that this is a branch off of logging utils rather than master is going to cause awful merge conflict issues down the line. Basically you have a "delete utils" commit after the canonical util creation commit. I put together some git to forcibly update the branch to a single commit in a branch from master. I'm sure that that a proper git wizard could do better (if a git wizard wants to chime in, feel free), but I think this will suffice for not confusing git down the line.

git checkout master
git pull --rebase

# make sure the branch is up to date save for our changes
git checkout feat/official-module
git pull --rebase origin master

# this branch is not intended to be pushed.
git checkout master  # (Forgot this the first time.)
git branch package_local
git checkout package_local

# pull the files of interest into our dummy branch
git checkout feat/official-module -- official/
git commit -m "Alter imports to act like a package."

# make sure things look good.
git log
git diff master package_local

# this should fail
git push --dry-run --set-upstream origin feat/official-module

# this should succeed.
git push --dry-run --set-upstream origin package_local

# When you're ready, actually pull the trigger.
git push -f --set-upstream origin feat/official-module

[karmel]

Thanks-- a few minor changes from my end, though it looks like py3 tests are failing whereas py2 is not? Any clues what is happening there?

[karmel]

While it's true that this will work, I think it's a little atypical to request that people actually cd in first. I think it might be preferable to instruct people that they have to add the top-level models folder to their python path, and illustrate like so:

export PYTHONPATH="$PYTHONPATH:/path/to/models"

Also, nit: in Github markdown, you should be able to use one backtick ( ` ) instead of three ( ``` ) for in-line code snippets.

[yhliang2018]

Thanks for the comments, Karmel!

For py3 test, I have submitted a CL to set up the python path, like what we did for py2. It should pass py3 tests once the CL is approved.

[yhliang2018]

@robieta Thank you for the detailed comments! Karmel also mentioned the same issue to me. Will update the branch as a single commit.

[qlzh727]

What I feel confused is that when I look at all file changed, it only shows the file from commit be8c1ba. Did u change/modify to some branch that overwrites your previous change?

[karmel]

Some minor text changes, but other than that, LGTM.

[karmel]

A few more nits that I started to type out, then realized it was easier just to show the end result:

## Running the models

The *Official Models* are made available as a Python module. To run the models and associated scripts, add the top-level ***/models*** folder to the Python path with the command: `export PYTHONPATH="$PYTHONPATH:/path/to/models"`

To make Official Models easier to use, we are planning to create a pip installable Official Models package. This is being tracked in [#917](https://github.com/tensorflow/models/issues/917).

[robieta]

This all seems quite reasonable.

[guxiaopihai]

运行mnist.py 出错，报The first layer in a Sequential model must get an input_shape argument.