def upgrade ta, td, a, d
  a["ldap"]["user_enabled_invert"] = ta["ldap"]["user_enabled_invert"]
  a["ldap"]["use_pool"] = ta["ldap"]["use_pool"]
  return a, d
end

def downgrade ta, td, a, d
  a["ldap"].delete("user_enabled_invert")
  a["ldap"].delete("use_pool")
  return a, d
end
