Fix comments and unittest for market.py and style

Trying to make the right commit to  the develop branch.
This indentation is misleading, as it makes you think these are arguments to `Thread`. Please restyle as follows:
```
t = Thread(
    target=self.transport.dth.iterativeStore,
    args=(
        self.transport,
        contract_key,
        str(singed_data),
        self.transport.guid
    )
)
```