You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: helper.rb
    path of file: ./repos/stackneveroverflow/vendor/bundle/ruby/2.3.0/gems/oauth-0.5.3/lib/oauth
    
    the code of the file until where you have to start completion: require 'openssl'
require 'base64'

module OAuth
  module Helper
    extend self

    # Escape +value+ by URL encoding all non-reserved character.
    #
    # See Also: {OAuth core spec version 1.0, section 5.1}[http://oauth.net/core/1.0#rfc.section.5.1]
    def escape(value)
      _escape(value.to_s.to_str)
    rescue ArgumentError
      _escape(value.to_s.to_str.force_encoding(Encoding::UTF_8))
    end

    def _escape(string)
      URI.escape(string, OAuth::RESERVED_CHARACTERS)
    end

    def unescape(value)
      URI.unescape(value.gsub('+', '%2B'))
    end

    # Generate a random key of up to +size+ bytes. The value returned is Base64 encoded with non-word
    # characters removed.
    def generate_key(size=32)
      Base64.encode64(OpenSSL::Random.random_bytes(size)).gsub(/\W/, '')
    end

    alias_method :generate_nonce, :generate_key

    def generate_timestamp #:nodoc:
      Time.now.to_i.to_s
    end

    # Normalize a +Hash+ of parameter values. Parameters are sorted by name, using lexicographical
    # byte value ordering. If two or more parameters share the same name, they are sorted by their value.
    # Parameters are concatenated in their sorted order into a single string. For each parameter, the name
    # is separated from the corresponding value by an "=" character, even if the value is empty. Each
    # name-value pair is separated by an "&" character.
    #
    # See Also: {OAuth core spec version 1.0, section 9.1.1}[http://oauth.net/core/1.0#rfc.section.9.1.1]
    def normalize(params)
      params.sort.map do |k, values|
        if values.is_a?(Array)
          # make sure the array has an element so we don't lose the key
          values << nil if values.empty?
          # multiple values were provided for a single key
          values.sort.collect do |v|
            [escape(k),escape(v)] * "="
          end
        elsif values.is_a?(Hash)
          normalize_nested_query(values, k)
        else
          [escape(k),escape(values)] * "="
        end
      end * "&"
    end

    #Returns a string representation of the Hash like in URL query string
    # build_nested_query({:level_1 => {:level_2 => ['value_1','value_2']}}, 'prefix'))
    #   #=> 
    
    def normalize(params)
      params.sort.map do |k, values|
        if values.is_a?(Array)
          # make sure the array has an element so we don't lose the key
          values << nil if values.empty?
          # multiple values were provided for a single key
          values.sort.collect do |v|
            [escape(k),escape(v)] * "="
          end
        elsif values.is_a?(Hash)
          normalize_nested_query(values, k)
        else
          [escape(k),escape(values)] * "="
        end
      end * "&"
    end

    #Returns a string representation of the Hash like in URL query string
    # build_nested_query({:level_1 => {:level_2 => ['value_1','value_2']}}, 'prefix'))
    #   #=> ["prefix%5Blevel_1%5D%5Blevel_2%5D%5B%5D=value_1", "prefix%5Blevel_1%5D%5Blevel_2%5D%5B%5D=value_2"]
    def normalize_nested_query(value, prefix = nil)
      case value
      when Array
        value.map do |v|
          normalize_nested_query(v, "#{prefix}[]")
        end.flatten.sort
      when Hash
        value.map do |k, v|
          normalize_nested_query(v, prefix ? "#{prefix}[#{k}]" : k)
        end.flatten.sort
      else
        [escape(prefix), escape(value)] * "="
      end
    end

    # Parse an Authorization / WWW-Authenticate header into a hash. Takes care of unescaping and
    # removing surrounding quotes. Raises a OAuth::Problem if the header is not parsable into a
    # valid hash. Does not validate the keys or values.
    #
    #   hash = parse_header(headers['Authorization'] || headers['WWW-Authenticate'])
    #   hash['oauth_timestamp']
    #     #=>"1234567890"
    #
    def parse_header(header)
      # decompose
      params = header[6,header.length].split(/[,=&]/)

      # odd number of arguments - must be a malformed header.
      raise OAuth::Problem.new("Invalid authorization header") if params.size % 2 != 0

      params.map! do |v|
        # strip and unescape
        val = unescape(v.strip)
        # strip quotes
        val.sub(/^\"(.*)\"$/, '\1')
      end

      # convert into a Hash
      Hash[*params.flatten]
    end

    def stringify_keys(hash)
      new_h = {}
      hash.each do |k, v|
        new_h[k.to_s] = v.is_a?(Hash) ? stringify_keys(v) : v
      end
      new_h
    end
  end
end