OpenStack 7 HEAT templates help!

Hello all,
I'm trying to deploy an overcloud composited by one controller node and two compute nodes.
I'm customizing the file controller.yaml. My goal is to configure nic2 and nic3 in bonding and nic4 for external network.
I begin with the /network/config/bond-with-vlans/controller.yaml and I just want to add a nic4 but I can't validate YAML syntax file because I don't know it :(

I paste the file I'm working for:

[stack@director nic-configs]$ cat controller.yaml
heat_template_version: 2015-04-30

description: >
Software Config to drive os-net-config with 2 bonded nics on a bridge
with a VLANs attached for the controller role.

parameters:
ExternalIpSubnet:
default: ''
description: IP address/subnet on the external network
type: string
InternalApiIpSubnet:
default: ''
description: IP address/subnet on the internal API network
type: string
StorageIpSubnet:
default: ''
description: IP address/subnet on the storage network
type: string
StorageMgmtIpSubnet:
default: ''
description: IP address/subnet on the storage mgmt network
type: string
TenantIpSubnet:
default: ''
description: IP address/subnet on the tenant network
type: string
BondInterfaceOvsOptions:
default: ''
description: The ovs_options string for the bond interface. Set things like
lacp=active and/or bond_mode=balance-slb using this option.
type: string
ExternalNetworkVlanID:
default: 10
description: Vlan ID for the external network traffic.
type: number
InternalApiNetworkVlanID:
default: 20
description: Vlan ID for the internal_api network traffic.
type: number
StorageNetworkVlanID:
default: 30
description: Vlan ID for the storage network traffic.
type: number
StorageMgmtNetworkVlanID:
default: 40
description: Vlan ID for the storage mgmt network traffic.
type: number
TenantNetworkVlanID:
default: 50
description: Vlan ID for the tenant network traffic.
type: number
ExternalInterfaceDefaultRoute:
default: '10.0.0.1'
description: default route for the external network
type: string

resources:
OsNetConfigImpl:
type: OS::Heat::StructuredConfig
properties:
group: os-apply-config
config:
os_net_config:
network_config:
-
type: ovs_bridge
name: {get_input: bridge_name}
members:
-
type: ovs_bond
name: bond1
ovs_options: {get_param: BondInterfaceOvsOptions}
members:
-
type: interface
name: nic2
primary: true
-
type: interface
name: nic3
-
type: vlan
device: bond1
vlan_id: {get_param: ExternalNetworkVlanID}
addresses:
-
ip_netmask: {get_param: ExternalIpSubnet}
routes:
-
ip_netmask: 0.0.0.0/0
next_hop: {get_param: ExternalInterfaceDefaultRoute}
-
type: vlan
device: bond1
vlan_id: {get_param: InternalApiNetworkVlanID}
addresses:
-
ip_netmask: {get_param: InternalApiIpSubnet}
-
type: vlan
device: bond1
vlan_id: {get_param: StorageNetworkVlanID}
addresses:
-
ip_netmask: {get_param: StorageIpSubnet}
-
type: vlan
device: bond1
vlan_id: {get_param: StorageMgmtNetworkVlanID}
addresses:
-
ip_netmask: {get_param: StorageMgmtIpSubnet}
-
type: vlan
device: bond1
vlan_id: {get_param: TenantNetworkVlanID}
addresses:
-
ip_netmask: {get_param: TenantIpSubnet}
- type: interface
name: nic4
addresses:
-
ip_netmask: {get_param: ExternalIpSubnet}
routes:
-
ip_netmask: 0.0.0.0/0
next_hop: {get_param: ExternalInterfaceDefaultRoute}

outputs:
OS::stack_id:
description: The OsNetConfigImpl resource.
value: {get_resource: OsNetConfigImpl}

Regards
Alessio Dini