Easing Map Get Function

I'm using a loop to save time; this would normally be used like so:

.ball {
    animation: there-and-back 2.5s ease(in-quad) infinite alternate;
}

Each "Ball" has a 2.5s alternating animation applied to it and the specified easing function listed directly ABOVE it.

Ease in-quad

Ease in-cubic

Ease in-quart

Ease in-quint

Ease in-sine

Ease in-expo

Ease in-circ

Ease in-back

Ease out-quad

Ease out-cubic

Ease out-quart

Ease out-quint

Ease out-sine

Ease out-expo

Ease out-circ

Ease out-back

Ease in-out-quad

Ease in-out-cubic

Ease in-out-quart

Ease in-out-quint

Ease in-out-sine

Ease in-out-expo

Ease in-out-circ

Ease in-out-back