diff --git a/libraries/common b/libraries/common
index fd74553..5cb1234 100644
--- a/libraries/common
+++ b/libraries/common
@@ -72,6 +72,15 @@ function fail() {
 	fi
 }
 
+#-------------------------------------------------------------------------------
+# Checks if the given function has been defined
+# Parameters: %function%
+#-------------------------------------------------------------------------------
+function functionExists() {
+	type ${1} 2>/dev/null | grep -q "is a function"
+	return ${?}
+}
+
 #-------------------------------------------------------------------------------
 # Checks whether a defined variable contain specified element or not
 # Parameters: %element% %variable%
diff --git a/modules/sample.ezmod b/modules/sample.ezmod
index c5c2472..a944f2e 100644
--- a/modules/sample.ezmod
+++ b/modules/sample.ezmod
@@ -2,3 +2,8 @@ EZMOD_DESCRIPTION="Sample module for learning and testing purposes"
 EZMOD_COMPATIBILITY="ezbuild ezsync"
 EZMOD_AUTHOR="Rafal Kupiec"
 EZMOD_VERSION="0.1"
+
+ezsync_postsync() {
+	printWarn "fdgdfs"
+#	return 1
+}