Ruby 'is_a?' class or module required (TypeError)

ruby while-loop integer conditional typeerror

You need to put the class Integer in parentheses:

unless @response.is_a?(Integer) && @response.to_str.length == 4

You are actually evaulating is_a? on (Integer && @response.to_str.length == 4) which is a boolean value, not a class or module.

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