Well, that doesn't work. You've got your syntax and data types all mixed up. 'foo' is not a subroutine, its a blessed object (and a scalar), and $Movement{key} is a method name (just a scalar and a string). If $foo were a subroutine reference and $Movement{key} were an argument to the subroutine, you could say:

$foo->($Movement{$key});
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But that's not the case here either.