Ask HN: CodeReview policy in your organization

What code review policies does your organization/team follow?

To clarify, my question is really about, if you are a developer, how does a code you write/change get approved for checking into your source control?

In our organization, we have about 25 software developers, and 3 development leads.

Among the 25 software developers, 5 of the developers are considered to be senior developers.

To be able to check-in a change, we need a sign-off/approval from one of the development leads or one of the senior developers.