[YANGUTILS]Error is throw if date is in format YYYY-M-D

Issue : Error is throw if date is in format YYYY-M-D

yang file :
module network {
yang-version 1;
namespace "urn:TBD:params:xml:ns:yang:nodes";
prefix nd;

import ietf-inet-types

{ prefix inet; }

organization "TBD";
contact
"WILL-BE-DEFINED-LATER";
description
"This module defines a common base model for a collection
of nodes in a network. Node definitions s are further used
in network topologies and inventories.";

revision 2014-3-9

{ description "Initial revision."; reference "draft-clemm-i2rs-yang-network-topo-04"; }

}

Output:
[INFO] Error in file: /home/root1/onos/utils/test/src/main/yang/network.yang at line: 16 at position: 5
YANG file error: Input date is not correct