Update Contributing.md

Contributing.md

@@ -29,3 +29,12 @@ Anything submitted to the issue tracker that does not follow these guidelines wi
 ## Writing Code
 
 If you are interested in contributing code, fixing open issues or adding features, please coordinate the effort with the maintainer or one of the main developers **before** submitting a pull request. Before deciding to contribute, it is also a good idea to ensure your efforts are in alignment with the [Roadmap](./Roadmap.md) and current development focus.
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+Pull requests have a high chance of being accepted if they are:
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+- In alignment with the [Roadmap](./Roadmap.md) or solve an open issue or feature request
+- Sufficiently tested to work with all API functions, and pass the standard test suite
+- Functionally and conceptually complete and well-designed
+- Well-documented
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+Even new ideas and proposals that have not been approved by a maintainer, or fall outside the established roadmap, are *occasionally* accepted - if they possess the remaining of the above qualities. If not, they will be closed and removed without comments or explanation.