Not entirely, but to some degree.
The normal process to add something like a new data structure is:
- Gather as much community feedback as you can, at a minimum here on Discuss or the Python-Ideas mailing list. (You can also discuss it on places like Reddit, or any other forum you like.)
- If the community seems to get behind the idea, or at least not be strongly opposed, the next step is to ask for a sponsor from the core developers.
- If at least one core dev is willing to act as sponsor, you (or somebody) should write a PEP proposing the feature.
- The PEP then gets sent back here for additional rounds of feedback.
- If there is sufficient community interest in the PEP, the author then asks the Steering Council to accept the PEP.
- If they accept it, then somebody (often the PEP author) will implement it and add it to the std lib.
Note that acceptance by the Steering Council does not necessary mean that there will be a volunteer willing and able to do the work needed to push the data structure into the std lib.