any_of doesn't work with variable input

I don't always know at write time what will go into an any_of query, but I can't do this:
arr = [{:condition1 => "foo"}, {:condition2 => "bar"}]
MyClass.any_of(arr)

1. nor
   MyClass.any_of(*arr)

1. Expected:
   MyClass.any_of(arr) == MyClass.any_of({:condition1 => "foo"}, {:condition2 => "bar"})
   Suggestions? Or maybe checking for an array arg could be patched in?