def get(user)
      mechanism = user.mechanism
      raise InvalidMechanism.new(mechanism) if !SOURCES.has_key?(mechanism)
      SOURCES[mechanism].new(user)
    end
def get(user)
      mechanism = user.mechanism
      raise InvalidMechanism.new(mechanism) if !SOURCES.has_key?(mechanism)
      SOURCES[mechanism].new(user)
    end
Get the authorization strategy for the provided auth mechanism.

 @example Get the strategy.
   Auth.get(user)

 @param [ Auth::User ] user The user object.

 @return [ CR, X509, LDAP, Kerberos ] The auth strategy.

 @since 2.0.0