diff --git a/src/main/kotlin/com/github/insanusmokrassar/PsychomatrixBase/domain/entities/MutablePsychomatrix.kt b/src/main/kotlin/com/github/insanusmokrassar/PsychomatrixBase/domain/entities/MutablePsychomatrix.kt
index 5a83acd..3c446dd 100644
--- a/src/main/kotlin/com/github/insanusmokrassar/PsychomatrixBase/domain/entities/MutablePsychomatrix.kt
+++ b/src/main/kotlin/com/github/insanusmokrassar/PsychomatrixBase/domain/entities/MutablePsychomatrix.kt
@@ -15,6 +15,8 @@ class MutablePsychomatrix(date: DateTime) : Psychomatrix(date) {
 
     private val mutableOperationsHistory: MutableList<Operation> = ArrayList()
 
+    constructor(psychomatrix: Psychomatrix): this(psychomatrix.date)
+
     val operationsHistory: List<Operation>
         get() = mutableOperationsHistory