respond_to?

        # Exception.respond_to?

(from ruby core)
### Implementation from Object
---
    obj.respond_to?(symbol, include_all=false) -> true or false
    obj.respond_to?(string, include_all=false) -> true or false

---

Returns `true` if *obj* responds to the given method.  Private and
protected methods are included in the search only if the optional second
parameter evaluates to `true`.

If the method is not implemented, as Process.fork on Windows,
File.lchmod on GNU/Linux, etc., false is returned.

If the method is not defined, `respond_to_missing?` method is called and
the result is returned.

When the method name parameter is given as a string, the string is
converted to a symbol.