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: signature.rb
    path of file: ./repos/arachni/lib/arachni/element/capabilities/analyzable
    
    the code of the file until where you have to start completion: =begin
    Copyright 2010-2022 Ecsypno <http://www.ecsypno.com>

    This file is part of the Arachni Framework project and is subject to
    redistribution and commercial restrictions. Please see the Arachni Framework
    web site for more information on licensing and terms of use.
=end

module Arachni
module Element::Capabilities
module Analyzable

# Looks for specific substrings or patterns in response bodies.
#
# @author Tasos "Zapotek" Laskos <tasos.laskos@arachni-scanner.com>
module Signature

    SIGNATURE_CACHE   = {
        match: Support::Cache::LeastRecentlyPushed.new( 10_000 )
    }

    SIGNATURE_OPTIONS = {
        # The signatures to look for in each line of the response body,
        # if `Regexp` it will be matched against it, if `String` it'll be used
        # as a needle.
        #
        # Multi-line Regexp is not supported.
        signatures: [],

        # Array of signatures to ignore.
        #
        # Useful when needing to narrow down what to log without having to
        # construct overly complex signatures.
        ignore:     []
    }

    FILE_SIGNATURES = {
        'environ'  => proc do |response|
            next if !response.body.include?( 'DOCUMENT_ROOT=' )
            /DOCUMENT_ROOT=.*HTTP_USER_AGENT=/
        end,
        'passwd'   => proc do |response|
            if response.body.includ
    
    def find_signatures( signatures, response, opts )
        k = [signatures, response.body]
        return if SIGNATURE_CACHE[:match][k] == false

        case signatures
            when Regexp, String, Array
                [signatures].flatten.compact.each do |signature|
                    res = find_signature( signature, response, opts )
                    SIGNATURE_CACHE[:match][k] ||= !!res
                end

            when Hash
                if opts[:platform] && signatures[opts[:platform]]
                    [signatures[opts[:platform]]].flatten.compact.each do |p|
                        [p].flatten.compact.each do |signature|
                            res = find_signature( signature, response, opts )
                            SIGNATURE_CACHE[:match][k] ||= !!res
                        end
                    end

                else
                    signatures.each do |platform, p|
                        dopts = opts.dup
                        dopts[:platform] = platform

                        [p].flatten.compact.each do |signature|
                            res = find_signature( signature, response, dopts )
                            SIGNATURE_CACHE[:match][k] ||= !!res
                        end
                    end
                end

                return if !opts[:payload_platforms]

                # Find out if there are any signatures without associated payloads
                # and match them against every payload's response.
                signatures.select { |p, _|  !opts[:payload_platforms].include?( p ) }.
                    each do |platform, p|
                        dopts = opts.dup
                        dopts[:platform] = platform

                        [p].flatten.compact.each do |signature|
                            res = find_signature( signature, response, dopts )
                            SIGNATURE_CACHE[:match][k] ||= !!res
                        end
                    end
        end
    end