The RNAi checker

A sense RNA and an antisense RNA are written as strings of letters. You will build the antisense strand, count the hydrogen bonds of the double strand, and test whether two strands are complementary.

The idea. In RNA, A pairs with U by $2$ hydrogen bonds, and G pairs with C by $3$.

Your tasks.

1. Finish antisense. It gives the strand that is complementary to the sense strand, written in the same order of positions.
2. Finish bonds. It gives the number of hydrogen bonds when the strand pairs along its whole length.
3. Finish complementary. It gives True if the two strands pair along the whole length.