>>> hex_string = "deadbeef"

Convert it to a string (Python ≤ 2.7):
    >>> hex_data = hex_string.decode("hex")
    >>> hex_data
    "\xde\xad\xbe\xef"
    
or since Python 2.7 and Python 3.0:
    >>> bytes.fromhex(hex_string)  # Python ≥ 3
    b'\xde\xad\xbe\xef'

    >>> bytearray.fromhex(hex_string)
    bytearray(b'\xde\xad\xbe\xef')