instance method validate

# File actionpack/lib/action_dispatch/http/content_security_policy.rb, line 334
      def validate(directive, sources)
        sources.flatten.each do |source|
          if source.include?(";") || source != source.gsub(/[[:space:]]/, "")
            raise InvalidDirectiveError, <<~MSG.squish
              Invalid Content Security Policy #{directive}: "#{source}".
              Directive values must not contain whitespace or semicolons.
              Please use multiple arguments or other directive methods instead.
            MSG
          end
        end
      end