Stringify booleans recusively in Arrays and Hashes

stringify_bools.rb

# Over-write method
def stringify_bools!(target)
  target.replace stringify_bools(target)
end

# Returns clone of target Array or Hash with all booleans within turned into strings
def stringify_bools(target)
  t_clone = target.clone
  
  raise ArgumentError, 'Target is neither Array or Hash' unless target.is_a?(Array) || target.is_a?(Hash)
  
  t_class = target.class.to_s
    
  if t_class == 'Array'
    t_clone.map! do |el|
      el = el.to_s if el.is_a?(TrueClass) || el.is_a?(FalseClass)
      el = stringify_bools(el) if el.is_a?(Array) || el.is_a?(Hash)
      
      el
    end
  elsif t_class == 'Hash'
    t_clone.each do |key, val|
      t_clone[key] = val.to_s if val.is_a?(TrueClass) || val.is_a?(FalseClass)
      t_clone[key] = stringify_bools(val) if val.is_a?(Array) || val.is_a?(Hash)
    end
  end
  
  t_clone
end

I was completely wrong, if statement performs better than case ( as per this article )