hiera_hash Cannot reassign variable '$network' in site.pp

site.pp $mysql = hiera_hash(mysql) $network = hiera_hash(network) $nfs = hiera_hash(nfs) default.json "mysql" : {}, "network" : {}, "nfs" : {}, This gives Cannot reassign variable '$network' at /etc/puppetlabs/code/environments/prod/manifests/site.pp Removing 'network' entry from default.json gives Could not find data item network in any Hiera data file and no default supplied at /etc/puppetlabs/code/environments/prod/manifests/site.pp Can anybody explain what's going on ?

Chris
Hiera v3.2, Puppet master 4 (2.4)

Well I did search for it, but all I got was grep -r network manifests/ manifests/site.pp:$network = hiera_hash(network) and grep -r \$network modules/ modules/network/manifests/classes/tagging/configuration.pp: if $network['vlan'] { modules/network/manifests/classes/tagging/configuration.pp: tagged_vlan { $network['vlan']: } which leads to define tagged_vlan() { file { "/etc/sysconfig/network-scripts/ifcfg-bond0.${name}": ensure => file, content => template('network/etc/sysconfig/network-scripts/ifcfg-bond0.erb') } file { "/etc/sysconfig/network-scripts/ifcfg-bridge0.${name}": ensure => file, content => template('network/etc/sysconfig/network-scripts/ifcfg-bridge0.erb') } ifcfg-eth-vlan{ "eth0.${name}": vlan => $name, interface => "eth0", } ifcfg-eth-vlan{ "eth1.${name}": vlan => $name, interface => "eth1", } }