```ruby
module Twilio
  module REST
    module Utils

      def twilify(something)
        if something.is_a? Hash
          Hash[*something.to_a.map {|a| [twilify(a[0]).to_sym, a[1]]}.flatten(1)]
        else
          something.to_s.split('_').map do |s|
            [s[0,1].capitalize, s[1..-1]].join
          end.join
        end
      end

      def detwilify(something)
        if something.is_a? Hash
          Hash[*something.to_a.map {|pair| [detwilify(pair[0]).to_sym, pair[1]]}.flatten]
        else
          something.to_s.gsub(/[A-Z][a-z]*/) {|s| "_#{s.downcase}"}.gsub(/^_/, '')
        end
      end

    end
  end
end
```

Change `map` to `map!` to save extra array creation on new array
user
```ruby
module Twilio
  module REST
    module Utils

      def twilify(something)
        if something.is_a? Hash
          Hash[*something.to_a.map! {|a| [twilify(a[0]).to_sym, a[1]]}.flatten(1)]
        else
          something.to_s.split('_').map! do |s|
            [s[0,1].capitalize, s[1..-1]].join
          end.join
        end
      end

      def detwilify(something)
        if something.is_a? Hash
          Hash[*something.to_a.map! {|pair| [detwilify(pair[0]).to_sym, pair[1]]}.flatten]
        else
          something.to_s.gsub(/[A-Z][a-z]*/) {|s| "_#{s.downcase}"}.gsub(/^_/, '')
        end
      end

    end
  end
end
```
assistant