Fix shadowed builtins, id -> id_

[delirious-lettuce]

Checklist

• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the [Contribution Guide] and my PR follows them.
• I updated my branch with the master branch.

Short description of what this PR does:

• Append a trailing underscore to fix shadowed builtin (id).
  Python has a builtin function named id so using id as a variable name can be problematic.

  If a function argument’s name clashes with a reserved keyword, it is generally better to append a single trailing underscore rather than use an abbreviation or spelling corruption.

[gabrielkrell]

id is one of those functions that I wish was named differently, just because it's such a common variable name compared to how often the function is used. Oh well, +1

[thinkingserious]

Hello @delirious-lettuce,

Thanks again for the PR!

We appreciate your contribution and look forward to continued collaboration. Thanks!

Team SendGrid DX