diff --git a/src/main/java/eu/dnetlib/validator2/validation/guideline/openaire/F3_01M.java b/src/main/java/eu/dnetlib/validator2/validation/guideline/openaire/F3_01M.java
index 97216a4..2c89b66 100644
--- a/src/main/java/eu/dnetlib/validator2/validation/guideline/openaire/F3_01M.java
+++ b/src/main/java/eu/dnetlib/validator2/validation/guideline/openaire/F3_01M.java
@@ -22,7 +22,7 @@ public final class F3_01M extends AbstractOpenAireProfile {
             "IGSN", "QID", "ARK", "IVOA", "CAS RN", "RRID", "URL", "RInChi", "ERM", "ISO 27729:2012 ISNI",
             "EC Number", "PURL", "LSID", "TFClass Schema", "InChI", "w3id", "Handle", "DOI", "ORCID iD", "arXiv"
     };
-
+ 
     private static final ElementSpec F3_01M_SPEC_1 = Builders.
             forMandatoryElement("identifier", ONE).
 //            withMandatoryAttribute("identifierType", new PIDCheckValuePredicate()).