The PEP abstract says this: "Static typing as defined by PEPs 484, 526, 544, 560, and 563 was built incrementally on top of the existing Python runtime and cons

The PEP abstract says this: "Static typing as defined by PEPs 484, 526, 544, 560, and 563 was built incrementally on top of the existing Python runtime and constrained by existing syntax and runtime behavior"