text: """MessageBird platform for notify component."""
  import logging
  
  import messagebird
  from messagebird.client import ErrorException
  import voluptuous as vol
  
  from homeassistant.components.notify import (
      ATTR_TARGET,
      PLATFORM_SCHEMA,
      BaseNotificationService,
  )
  from homeassistant.const import CONF_API_KEY, CONF_SENDER
  import homeassistant.helpers.config_validation as cv
  
  _LOGGER = logging.getLogger(__name__)
  
  PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
      {
          vol.Required(CONF_API_KEY): cv.string,
          vol.Optional(CONF_SENDER, default="HA"): vol.All(
              cv.string, vol.Match(r"^(\+?[1-9]\d{1,14}|\w{1,11})$")
          ),
      }
  )
  
  
  def get_service(hass, config, discovery_info=None):
      """Get the MessageBird notification service."""
      client = messagebird.Client(config[CONF_API_KEY])
      try:
          # validates the api key
          client.balance()
      except messagebird.client.ErrorException:
          _LOGGER.error("The specified MessageBird API key is invalid")
          return None
  
      return MessageBirdNotificationService(config.get(CONF_SENDER), client)
  
  
  class MessageBirdNotificationService(BaseNotificationService):
      """Implement the notification service for MessageBird."""
  
      def __init__(self, sender, client):
          """Initialize the service."""
          self.sender = sender
          self.client = client
  
      def send_message(self, message=None, **kwargs):
          """Send a message to a specified target."""
          targets = kwargs.get(ATTR_TARGET)
          if not targets:
              _LOGGER.error("No target specified")
              return
  
          for target in targets:
              try:
                  self.client.message_create(
                      self.sender, target, message, {"reference": "HA"}
                  )
              except ErrorException as exception:
                  _LOGGER.error("Failed to notify %s: %s", target, exception)
                  continue
  