Serial Packages OC

binary.py

class Binary(object):   
    def __init__(self, bits):
        self._bits = bits
    
    def write(self, device):
        device.write(self._bits)
    
    def read(self, device, length):
        self._bits = device.read(length)

data.py

class Data(object):
    def __init__(self):
        self.binary = Binary()
        
    def write(self, device):
        self.binary.write(device)
        
    def read(self, device, length):
        self.binary.read(device, length)

device.py

class Device(object):
    def __init__(self):
        self.ser = Serial()
        
    def write(self, bytes):
        return self.ser.write(bytes)
        
    def read(self, length):
        return self.ser.read(length)

header.py

class Header(object):
    def __init__(self):
        self.binary = Binary()
        
    def write(self, device):
        self.binary.write(device)
        
    def read(self, device, length=7):
        self.binary.read(device, length)

package.py

class Package(object):
    def __init__(self):
        self.header = Header()
        self.data = Data()
    
    def write(self, device):
        self.header.write(device)
        self.data.write(device)
    
    def read(self, device):
        self.header.read(device)
        # HowTo getLength from header?
        self.data.read(device, length)