  DP-coloring (also known as correspondence coloring) is a generalization of
list coloring, introduced by Dvo\v{r}\'ak and Postle in 2017. It is well-known
that there are non-4-choosable planar graphs. Much attention has recently been
put on sufficient conditions for planar graphs to be DP-$4$-colorable. In
particular, for each $k \in \{3, 4, 5, 6\}$, every planar graph without
$k$-cycles is DP-$4$-colorable. In this paper, we prove that every planar graph
without $7$-cycles and butterflies is DP-$4$-colorable. Our proof can be easily
modified to prove other sufficient conditions that forbid clusters formed by
many triangles.
