Fusions in an embryo sac

A flowering plant has $7$ chromosomes in one set. You will work out the chromosome numbers made by double fertilisation, and then count the seeds and the male gametes in a flower where only some ovules received a pollen tube.

The idea. Syngamy joins one male gamete to the egg. Triple fusion joins the other male gamete to the two polar nuclei. Each ovule that becomes a seed uses both gametes of one pollen tube.

Your tasks.

1. Set zygote to the chromosomes in the zygote.
2. Set pen to the chromosomes in the primary endosperm nucleus.
3. Set seeds to the number of ovules that received a pollen tube (a True in reached).
4. Set gametes_used to the number of male gametes used for those seeds.