def gem_signature(gem_full_name)
      require 'digest'

      Digest::SHA256.new.hexdigest(@gems[gem_full_name].to_yaml).to_s
    end
def gem_signature(gem_full_name)
      require 'digest'

      Digest::SHA256.new.hexdigest(@gems[gem_full_name].to_yaml).to_s
    end
The signature for the given gem specification.