diff --git a/manifests/server/grant_role.pp b/manifests/server/grant_role.pp
index 04729d4..6b9a606 100644
--- a/manifests/server/grant_role.pp
+++ b/manifests/server/grant_role.pp
@@ -1,51 +1,43 @@
 # Define for granting membership to a role. See README.md for more information
 define postgresql::server::grant_role (
-  $group,
-  $role             = $name,
+  String $group,
+  String $role      = $name,
   $ensure           = 'present',
   $psql_db          = $postgresql::server::default_database,
   $psql_user        = $postgresql::server::user,
   $port             = $postgresql::server::port,
   $connect_settings = $postgresql::server::default_connect_settings,
 ) {
-  validate_string($group)
-  validate_string($role)
-  if empty($group) {
-    fail('$group must be set')
-  }
-  if empty($role) {
-    fail('$role must be set')
-  }
   case $ensure {
     'present': {
       $command = "GRANT \"${group}\" TO \"${role}\""
       $unless_comp = '='
     }
     'absent': {
       $command = "REVOKE \"${group}\" FROM \"${role}\""
       $unless_comp = '!='
     }
     default: {
       fail("Unknown value for ensure '${ensure}'.")
     }
   }
 
   postgresql_psql { "grant_role:${name}":
     command          => $command,
     unless           => "SELECT 1 WHERE EXISTS (SELECT 1 FROM pg_roles AS r_role JOIN pg_auth_members AS am ON r_role.oid = am.member JOIN pg_roles AS r_group ON r_group.oid = am.roleid WHERE r_group.rolname = '${group}' AND r_role.rolname = '${role}') ${unless_comp} true",
     db               => $psql_db,
     psql_user        => $psql_user,
     port             => $port,
     connect_settings => $connect_settings,
   }
 
   if ! $connect_settings or empty($connect_settings) {
     Class['postgresql::server']->Postgresql_psql["grant_role:${name}"]
   }
   if defined(Postgresql::Server::Role[$role]) {
     Postgresql::Server::Role[$role]->Postgresql_psql["grant_role:${name}"]
   }
   if defined(Postgresql::Server::Role[$group]) {
     Postgresql::Server::Role[$group]->Postgresql_psql["grant_role:${name}"]
   }
 }