steps/machine_setup.py

from steps import step
import subprocess
import sh

class MachineSetup(step.Step):
    def run_script(self):
        """Sets up the firmware machine environment used by the build"""
        sh.cd(self.main_repo_name)

        # command = "export MACHINE=machine0 && source setup machine0 && umask002 "
        command = " && ".join([self.export_machine(), self.source_setup(), self.umask()])

        subprocess.run(["bash", "-c", command])