Function check_to_a 

pub fn check_to_a(interp: &mut Artichoke, value: Value) -> Result<Value, Error>

Fallible coercion of the given value to a Ruby Array or nil via #to_a.

If the given value is a array, it is returned. If the give value responds to a #to_a method, it is called. Otherwise, a TypeError is raised.

If this function returns Ok, the returned Value is guaranteed to be either a Ruby Array or nil.

Errors

• If the call to #to_a returns an error, that error is returned.
• If the call to #to_a returns anything other than an Array or nil, a TypeError is returned.