Difficult to attach one extra module to a web3 instance..

[pipermerriam]

What was wrong?

There is no simple way to include a custom module in a web3 instance while still also including all of the default modules.

How can it be fixed?

Ideally it should be a one-liner

class Foo(ModuleV2):
    ...

w3 = Web3(...)
w3.attach('foo', Foo)

# or

w3 = Web3(..., extra_modules=(('foo', Foo),)