func (m *Map) GetString(name string) string {
	m.schema.assertKeyType(name, String)
	return m.GetRaw(name)
}
func (m *Map) GetString(name string) string {
	m.schema.assertKeyType(name, String)
	return m.GetRaw(name)
}
// GetString returns the value of the given key, which must be of type String.