return collectDescendantsOfType { ktFunction ->
        // Name check
        if (ktFunction.fqName?.asString() != functionFqName) {
            return@collectDescendantsOfType false
        }

        // Preliminary extension function check
        val extensionCandidate = couldBeExtensionFunction && ktFunction.receiverTypeReference != null &&
            method.firstParameterMatches(ktFunction.receiverTypeReference!!) &&

    *   Support taking gradients of V2 `tf.cond` and `tf.while_loop` using
        `LookupTable`.
    *   Fix bug where `vectorized_map` failed on inputs with unknown static
        shape.
    *   Add preliminary support for sparse CSR matrices.
    *   Tensor equality with `None` now behaves as expected.
    *   Make calls to `tf.function(f)()`, `tf.function(f).get_concrete_function`

- Using `--log-file` is known to be problematic in 1.15. This presents as things being logged multiple times to the same file. The behaviour and details of this issue, as well as some preliminary attempts at fixing it are documented [here](https://github.com/kubernetes/kubernetes/issues/78734#issuecomment-501372131)

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)