code: def read(bar, offset, size):
      
      verify_access_range(bar, offset, size)
      if bar.type == 'io': return io_read(bar, offset, size)
      if bar.type == 'mem': return mem_read(bar, offset, size)
      return b''
docs: Read PCI data register.
      
      Parameters
      ----------
      bar : BaseAddressRegister
          BAR to read.
      
      offset : int
          Address offset in BAR to read.
      
      size : int
          Data size to read.
          
      Returns
      -------
      bytes
          Data read from BAR
          
      Examples
      --------
      >>> b = pypci.lspci(vendor=0x1147, device=3214)
      >>> pypci.read(b[0].bar[2], 0x0c, 4)
      b'\x00\x00\x00\x0c'