Where does hydrogen iodide cut the ether?

You will write three functions for the cleavage of ethers. Each group on the oxygen is one of "methyl", "primary", "secondary", "tertiary" or "aryl".

The idea. An aryl group never becomes the iodide. A tertiary group does, when there is one. Otherwise the less crowded group becomes the iodide. With excess HI the alcohol that comes off is converted as well, except for a phenol.

Your tasks.

1. Complete iodide_group(first, second) so that it returns the group that becomes the alkyl iodide.
2. Complete hi_used(first, second) so that it returns the moles of HI that one mole of the ether uses with excess HI: 2 for two alkyl groups, and 1 when one group is aryl.
3. Complete count_phenols(ethers) so that it returns how many of the ethers in a list give a phenol.