You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: dialog_field_validation.rb
    path of file: ./repos/manageiq/app/models/manageiq/providers/cloud_manager/provision_workflow
    
    the code of the file until where you have to start completion: # These methods are available for dialog field validation, do
    
  def validate_cloud_network(field, values, dlg, fld, value)
    return nil if value.present?
    return nil if get_value(values[:placement_auto])
    return nil if get_value(values[field]).present?

    "#{required_description(dlg, fld)} is required"
  end