def  get_tech(tech_name)
      if @techlist.include?(tech_name)
          if tech_name == 'MifareClassic'
              return NFCTagTechnology_MifareClassic.new()
          end
          if tech_name == 'MifareUltralight'
              return NFCTagTechnology_MifareULtralight.new()
          end
          if tech_name == 'Ndef'
              return NFCTagTechnology_Ndef.new()
          end
          if tech_name == 'NfcA'
              return NFCTagTechnology_NfcA.new()
          end
          if tech_name == 'IsoDep'
              return NFCTagTechnology_IsoDep.new()
          end
          if tech_name == 'NdefFormatable'
              return NFCTagTechnology_NdefFormatable.new()
          end
          if tech_name == 'NfcB'
              return NFCTagTechnology_NfcB.new()
          end
          if tech_name == 'NfcF'
              return NFCTagTechnology_NfcF.new()
          end
          if tech_name == 'NfcV'
              return NFCTagTechnology_NfcV.new()
          end
      else
          return nil
      end
  end
def  get_tech(tech_name)
      if @techlist.include?(tech_name)
          if tech_name == 'MifareClassic'
              return NFCTagTechnology_MifareClassic.new()
          end
          if tech_name == 'MifareUltralight'
              return NFCTagTechnology_MifareULtralight.new()
          end
          if tech_name == 'Ndef'
              return NFCTagTechnology_Ndef.new()
          end
          if tech_name == 'NfcA'
              return NFCTagTechnology_NfcA.new()
          end
          if tech_name == 'IsoDep'
              return NFCTagTechnology_IsoDep.new()
          end
          if tech_name == 'NdefFormatable'
              return NFCTagTechnology_NdefFormatable.new()
          end
          if tech_name == 'NfcB'
              return NFCTagTechnology_NfcB.new()
          end
          if tech_name == 'NfcF'
              return NFCTagTechnology_NfcF.new()
          end
          if tech_name == 'NfcV'
              return NFCTagTechnology_NfcV.new()
          end
      else
          return nil
      end
  end
return instance of coresponded tech (based on NFCTagTechnology)