# File lib/neo4jr-social/format_handler.rb, line 38
    def charset(val=nil)
      fail "Content-Type must be set in order to specify a charset" if response['Content-Type'].nil?

      if response['Content-Type'] =~ /charset=[^;]+/
        response['Content-Type'].sub!(/charset=[^;]+/, (val == '' && '') || "charset=#{val}")
      else
        response['Content-Type'] += ";charset=#{val}"
      end unless val.nil?

      response['Content-Type'][/charset=([^;]+)/, 1]
    end