Constant Py_TPFLAGS_HAVE_VECTORCALL 

pub const Py_TPFLAGS_HAVE_VECTORCALL: u64 = _ /* 2_048u64 */;

Available on crate feature tls and (Py_3_12, or Py_3_8 and non-Py_LIMITED_API) only.

Set if the type implements the vectorcall protocol (PEP 590)