feat: make network configurable via NETWORK environment variable

[Mounil2005]

Description:
Make Hedera network selection configurable via the NETWORK environment variable instead of hardcoding "testnet".
This improves flexibility for developers running on mainnet, previewnet, or solo.

• Replace hardcoded "testnet" default with os.getenv("NETWORK", "testnet")
• Update Network class to prioritize: explicit constructor arg → NETWORK env var → "testnet" fallback

Related issue(s):

Fixes #253

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[Mounil2005]

@exploreriii @nadineloepfe pls review and check

[Mounil2005]

Looks great but I think the next step is to change hardcoded instances in the examples i.e. from network = Network(network='testnet') to network = Network() or similar

I have updated all instances in the examples. Pls check @exploreriii

[Mounil2005]

@exploreriii any more changes needed??

[exploreriii]

Thank you Mounil

[nadineloepfe]

Thank you @Mounil2005!
However, I think it would be better to align this with the other SDKs and to not hardcode testnet in the Network class.
The Network should be explicitly set by the user.

However, how about this in the examples:

network = Network(os.getenv("NETWORK", "testnet"))

?

[exploreriii]

Hi @Mounil2005 is the requested change clear? Let us know if you need any clarifications

[Mounil2005]

Hi @Mounil2005 is the requested change clear? Let us know if you need any clarifications

Hello maam, hope you are doing well, the changes are clear but actually i didnt work on them cause currently my Uni exams are going on back-to-back…I request you to pls give me time till this weekend. I will work on it.

[exploreriii]

No problem, thank you for the update

[Mounil2005]

No problem, thank you for the update

Thank you for understanding ma'am.

[Mounil2005]

Thank you @Mounil2005! However, I think it would be better to align this with the other SDKs and to not hardcode testnet in the Network class. The Network should be explicitly set by the user.

However, how about this in the examples:

network = Network(os.getenv("NETWORK", "testnet"))

?

Thanks for the feedback!
I’ll update the PR so that the Network class does not default to "testnet" internally.
Instead, I’ll change the examples to use:
network = Network(os.getenv("NETWORK", "testnet"))

[exploreriii]

Thanks, also please note we have a new update 0.1.5 so the changelog, this would need to be added under unreleased above it

[exploreriii]

Hi Mounil, let me know when this is ready to review - thank you

[Mounil2005]

Hi Mounil, let me know when this is ready to review - thank you

yes maam, i will surely let u know

[exploreriii]

Hi @Mounil2005
We will be releasing 0.1.6 which will require another rebase and a changelog update from 0.1.5 to 0.1.6
Many thanks

[exploreriii]

Hi @Mounil2005 closing this issue down as coincidentally another PR that is nearly ready to merge solves this issue.
Sorry about the inconvenience, thank you for your efforts, and please feel free to contribute to another PR