Existence of single() method for bond potentials

Pair and Bond classes have a single() method to compute the force between a single pair of particles.
The pair class has also an int single_enable to indicate if the single() method exist or not.
It seems to me that there is not a similar flag in the Bond class. Is this the case?
How can I determine if the single() method exists for a given bond potential?
The following line in bond.h defines the virtual method but it is not specific to any bond potential:
virtual double single(int, double, int, int, double &) = 0;


This is a “pure” function definition. Note the = 0!

This means that every class, that is derived from the Bond base class, must implement this function: 3.6. Bond, angle, dihedral, improper styles — LAMMPS documentation
Please check your favorite C++ reference for confirmation.

In Pair the equivalent function has a dummy implementation which makes this an optional function for any derived class: 3.5. Pair styles — LAMMPS documentation

Thanks a lot for your prompt reply ! Really helpful as always