def hex_val_str(val,bytes_to_fill,prefix='0x'):
  ret_str = ''
  if bytes_to_fill ==   1:
    ret_str = '{2}{0:0{1}X}'.format(val,2,prefix)
  elif bytes_to_fill == 2:
    ret_str = '{2}{0:0{1}X}'.format(val,4,prefix)
  elif bytes_to_fill == 4:
    ret_str = '{2}{0:0{1}X}'.format(val,8,prefix)
  return ret_str

def hex_bytes_to_str(hex_bytes,prefix='0x',sep=' '):
  hex_str=''
  for data in hex_bytes:
    hex_str = hex_str + hex_val_str(data,1,prefix) + sep
  return hex_str

def hex_str_to_bytes(hex_str):
  return bytes.fromhex(hex_str)