Spree overriding helper method

I'm trying to overriding a helper method of base_helper.rb by using this:

module Spree
  module BaseHelper.class_eval do

    def taxons_tree(root_taxon, current_taxon, max_level = 1)
      .....
    end

  end
end

It's not working for me. Anyone know what I am missing here?

Thank you!

Fixed:

I should use:

Spree::BaseHelper.module_eval do

    def taxons_tree(root_taxon, current_taxon, max_level = 1)
      ...
    end

end

instead.