A type 
L meets the 
Cpp17TimedLockable requirements if it meets the 
Cpp17Lockable
requirements and the following expressions are well-formed and have the specified semantics
(
m denotes a value of type 
L, 
rel_time denotes a value of an
instantiation of 
duration (
[time.duration]), and 
abs_time denotes a value
of an instantiation of 
time_point (
[time.point]))
.