Update readme

README.md

@@ -7,12 +7,14 @@ This library provides a way to frame and send data safely over serial, this incl
 ### Framing data
 
 ```python
+from sfp.sfp import frame_data
+import binascii
+
 # The data to be framed
 data = bytearray([0x12, 0x34, 0x56])
 
 # Frame and store the result in framed_data
-framed_data = bytearray()
-frame_data(data, framed_data)
+framed_data = frame_data(data)
 
 # Print the hexadecimal representation of the result
 # This will return b'7e0003123456bf127f'
@@ -30,12 +32,14 @@ In those bytes:
 ### Unframing data
 
 ```python
+from sfp.sfp import unframe_data
+import binascii
+
 # The frame to unframe the data from
 framed_data = bytearray([0x7e, 0x0, 0x3, 0x12, 0x34, 0x56, 0xbf, 0x12, 0x7f])
 
 # Unframe and store the result in unframed_data
-unframed_data = bytearray()
-unframe_data(framed_data, unframed_data)
+unframed_data = unframe_data(framed_data)
 
 # Print the hexadecimal representation of the result
 # This will return b'123456'