An oxide classifier

You will look up the acid-base character of the oxides of groups 13 and 14, count them, and test whether a series follows the trend down a group.

The idea. Down a group, an oxide becomes less acidic. We can put the four characters in a scale: acidic, then amphoteric, then basic.

Your tasks.

1. Complete character(oxide) so that it returns the character of an oxide from the table.
2. Complete count(kind) so that it returns how many oxides in the table have that character.
3. Complete less_acidic(a, b) so that it is true when oxide a is further along the scale than oxide b.
4. Complete follows_trend(series) so that it is true when each oxide of the series is not more acidic than the one before it.