$20\mathrm{.}5\mathrm{.}3$: Write a method that returns a new map with common key$-$value pairs.

$597714\mathrm{.}2988516.$qx$3$zqy$7$

Write a method that, given two maps, yields a map with all key$/$value associations that are common to both maps. That is$,$ the same key must map to the same value in both maps.