class RuboCop::Cop::Performance::Sum

def build_method_bad_method(init, method, operation)
  bad_method = "#{method}("
  unless init.empty?
    init = init.first
    bad_method += "#{init.source}, "
  end
  bad_method += if operation.block_pass_type?
                  '&:+)'
                else
                  ':+)'
                end
  bad_method
end