entry points, one that is callable from normal Python code using the
Python call semantics and Python objects as arguments, and one that is
callable from C code with fast C semantics and without requiring
-intermediate argument conversion from or to Python types.
+intermediate argument conversion from or to Python types. Note that ``cpdef``
+methods ensure that they can be appropriately overridden by Python
+methods even when they are called from Cython. This adds a tiny overhead
+compared to ``cdef`` methods.
The following listing shows the complete implementation that uses
``cpdef`` methods where possible::