Using Python to add text lines in a gcode file

[Johnlab]

I have been building a 3D printer and would like to create a post-processing plugin for my slicer as the slicer doesn't provide a feature that I require. I'm using Cura as a slicer and it accepts python scripts as plugins to modify the generated Gcode as a built-in feature. Here is a (shortened) sample of the generated gcode:

Output:
;LAYER_COUNT:191  
;LAYER:0  
M106 S255  
G0 F3600 X99.873 Y99.731 Z0.3  
;TYPE:WALL-INNER  
G1 F1800 X100.034 Y99.574 E0.02699  
G1 X100.225 Y99.441 E0.05491  
G1 X100.445 Y99.339 E0.08401  
;TIME_ELAPSED:18.234693  
;LAYER:1  
M107  
G0 F5400 X99.456 Y98.484 Z0.45  
;TYPE:WALL-INNER  
M106 255  
G1 F3300 X99.604 Y98.363 E47.83319  
G1 X99.774 Y98.299 E47.84409  
G1 X100.033 Y98.238 E47.86005  
G0 X99.568 Y98.521  
;TIME_ELAPSED:37.123855  
;LAYER:2  
M107  
G0 F7200 X98.896 Y97.697 Z0.6  
;TYPE:WALL-INNER  
M106 255  
G1 F4800 X99.103 Y97.5 E80.19273  
G1 X99.378 Y97.417 E80.20996  
G1 X99.486 Y97.403 E80.2165  
G0 X107.174 Y111.477  
;TIME_ELAPSED:1240.100936  
M107  

;End of Gcode  

After each Z#.## move, I would like to insert some more lines of Gcode underneath. This could be done by looking at "LAYER" and inserting sample code 3 lines under. This is some sample code of what I would like to add.

Output:
G0 X100 Y50  
G1 F100 X100 Y10  
G1 F20 X110 Y10  
G1 F100 X110 Y170  
G1 F100 X110 Y10  
G1 F20 X100 Y10  
G0 X100 Y50  

So the end result would be:

Output:
;LAYER_COUNT:191  
;LAYER:0  
M106 S255  
G0 F3600 X99.873 Y99.731 Z0.3  
G0 X100 Y50  
G1 F100 X100 Y10  
G1 F20 X110 Y10  
G1 F100 X110 Y170  
G1 F100 X110 Y10  
G1 F20 X100 Y10  
G0 X100 Y50  
;TYPE:WALL-INNER  
G1 F1800 X100.034 Y99.574 E0.02699  
G1 X100.225 Y99.441 E0.05491  
G1 X100.445 Y99.339 E0.08401  
;TIME_ELAPSED:18.234693  
;LAYER:1  
M107  
G0 F5400 X99.456 Y98.484 Z0.45  
G0 X100 Y50  
G1 F100 X100 Y10  
G1 F20 X110 Y10  
G1 F100 X110 Y170  
G1 F100 X110 Y10  
G1 F20 X100 Y10  
G0 X100 Y50  
;TYPE:WALL-INNER  
M106 255  
G1 F3300 X99.604 Y98.363 E47.83319  
G1 X99.774 Y98.299 E47.84409  
G1 X100.033 Y98.238 E47.86005  
G0 X99.568 Y98.521  
;TIME_ELAPSED:37.123855  
;LAYER:2  
M107  
G0 F7200 X98.896 Y97.697 Z0.6  
G0 X100 Y50  
G1 F100 X100 Y10  
G1 F20 X110 Y10  
G1 F100 X110 Y170  
G1 F100 X110 Y10  
G1 F20 X100 Y10  
G0 X100 Y50  
;TYPE:WALL-INNER  
M106 255  
G1 F4800 X99.103 Y97.5 E80.19273  
G1 X99.378 Y97.417 E80.20996  
G1 X99.486 Y97.403 E80.2165  
G0 X107.174 Y111.477  
;TIME_ELAPSED:1240.100936  
M107  

;End of Gcode  

Any Help Would be appreciated

Thanks