find_root! is not available in early versions of DataStructures

Author: Krastanov

Project.toml

@@ -17,7 +17,7 @@ Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 [compat]
 ArnoldiMethod = "0.4"
 Distributed = "1"
-DataStructures = "0.17, 0.18, 0.19"
+DataStructures = "0.18, 0.19"
 Inflate = "0.1.3"
 LinearAlgebra = "1"
 Random = "1"