code: def jtag_configure(self, instr_regs=0, data_bits=0):
          
          if not util.is_natural(instr_regs):
              raise ValueError('IR value is not a natural number.')
  
          if not util.is_natural(data_bits):
              raise ValueError('Data bits is not a natural number.')
  
          self._dll.JLINKARM_ConfigJTAG(instr_regs, data_bits)
          return None
docs: Configures the JTAG scan chain to determine which CPU to address.
  
          Must be called if the J-Link is connected to a JTAG scan chain with
          multiple devices.
  
          Args:
            self (JLink): the ``JLink`` instance
            instr_regs (int): length of instruction registers of all devices
              closer to TD1 then the addressed CPU
            data_bits (int): total number of data bits closer to TD1 than the
              addressed CPU
  
          Returns:
            ``None``
  
          Raises:
            ValueError: if ``instr_regs`` or ``data_bits`` are not natural numbers