Check if package is installed before enforcing configured version

Customer has asked me to create a feature request to allow them to check if a package is installed before puppet enforces the configured version.

For example, customer would like to be able to do something like this:

$packages =

{   'puppet' => \{ ensure => '6.14.0-1.el7' }

,
  'ntp' => { ensure => '1.5.3-1' },
}

keys($pkg_hash).each |Integer $index, String $pkg| {
  if ! $facts['_puppet_inventory_1']['packages'][$pkg]['1']

{     $upgrade=undef   }

  elsif versioncmp($facts['_puppet_inventory_1']['packages'][$pkg]['1'], ${attributes['ensure']}) == "1"

{     $upgrade=False   }

  elsif versioncmp($facts['_puppet_inventory_1']['packages'][$pkg]['1'], ${attributes['ensure']}) == "-1"

{     $upgrade=True   }

if ($upgrade == undef) or ($upgrade) {
  package

{ $pkg:     ensure => $attributes['ensure'],   }

}
}