Turn on the instant pot on saute mode and add oil. When the oil gets hot, add mustard seeds. Let them pop and then add chana dal, urad dal and cumin seeds. Once the dal gets light brown add the chopped curry leaves and saute for 10 seconds.
Now add garlic and frozen french cut beans and mix it. Now add the turmeric powder, coriander powder, red chili powder, garam masala, brown sugar and salt and cook for 30 seconds.
Add ¼ cup of water, give a mix and cancel the sauté mode. Close the lid and adjust the vent to the sealing position. Press the manual or pressure cooker mode and adjust the time to 3 minutes on high pressure.
Once the cooking time is done, do a natural pressure release.
Add lemon juice and coriander. Mix it and taste for seasoning. Adjust salt, lemon juice or sugar if needed.