I am working on implementing a new action within q2-fragment-insertion. There is software that I believe is necessary to run one of the preexisting actions and I am not sure how it is imported or loaded. Understanding how certain plugins in the core distribution import their dependencies would greatly help me determine from where a specific script is being imported from.
Hi @Daniela_Perry1,
Welcome to the 
forum!
q2-fragment-insertion uses sepp under the hood, and the specific script that you're referencing can be found here.
The segment of code you referenced is making a subprocess call to a command within the sepp package. This package is imported as a run requirement for q2-fragment-insertion - which means it's a required dependency in order for q2-fragment-insertion to successfully run. All of the package dependencies (separated by the type of requirement they are - i.e. run, test, etc) can be found here:
In your development environment you'll need to make sure that you have all of these package dependencies installed (either via conda install <package-name> or pip install <package-name>) in order for commands to run successfully.
Hope this helps! Cheers 
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