1 files changed, 26 insertions, 0 deletions
diff --git a/entity/err.go b/entity/err.go
index 9356433d..7022305c 100644
--- a/entity/err.go
+++ b/entity/err.go
@@ -1 +1,27 @@
 package entity
+
+import (
+	"fmt"
+	"strings"
+)
+
+type ErrMultipleMatch struct {
+	entityType string
+	Matching   []Id
+}
+
+func NewErrMultipleMatch(entityType string, matching []Id) *ErrMultipleMatch {
+	return &ErrMultipleMatch{entityType: entityType, Matching: matching}
+}
+
+func (e ErrMultipleMatch) Error() string {
+	matching := make([]string, len(e.Matching))
+
+	for i, match := range e.Matching {
+		matching[i] = match.String()
+	}
+
+	return fmt.Sprintf("Multiple matching %s found:\n%s",
+		e.entityType,
+		strings.Join(matching, "\n"))
+}