[Python] What is the recommended way to extend Python modules with custom functionality...

I maintain a large scientific Python application that uses several third-party modules like PyQtGraph (for plotting) and PyMeasure (for instrument control). I frequently need to add small custom features to these libraries.

For example, adding plot modes like normalize=True (Y scaled to 0–1) or tmr=True (TMR % display) to PyQtGraph:

plot.plot(x, y, normalize=True)


Previously I handled this by downloading the package source and editing files directly:

pip download pyqtgraph # or pymeasure
# unzip → edit PlotDataItem.py or Instrument.py
pip install ./my-modified-package


This is no longer viable: package updates break everything.

What are the preferred Python patterns for extending third-party modules.

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