sum(init = nil, &block)
Array#sum was added in Ruby 2.4 but it only works with Numeric elements.
# File activesupport/lib/active_support/core_ext/enumerable.rb, line 241 def sum(init = nil, &block) if init.is_a?(Numeric) || first.is_a?(Numeric) init ||= 0 orig_sum(init, &block) else super end end