old_contents: """Build OSC bundles for client applications."""
  
  from pythonosc import osc_bundle
  from pythonosc import osc_message
  from pythonosc.parsing import osc_types
  
  # Shortcut to specify an immediate execution of messages in the bundle.
  IMMEDIATELY = osc_types.IMMEDIATELY
  
  
  class BuildError(Exception):
      """Error raised when an error occurs building the bundle."""
  
  
  class OscBundleBuilder(object):
      """Builds arbitrary OscBundle instances."""
  
      def __init__(self, timestamp):
          """Build a new bundle with the associated timestamp.
  
          Args:
            - timestamp: system time represented as a floating point number of
                         seconds since the epoch in UTC or IMMEDIATELY.
          """
          self._timestamp = timestamp
          self._contents = []
  
      def add_content(self, content):
          """Add a new content to this bundle.
  
          Args:
            - content: Either an OscBundle or an OscMessage
          """
          self._contents.append(content)
  
      def build(self):
          """Build an OscBundle with the current state of this builder.
  
          Raises:
            - BuildError: if we could not build the bundle.
          """
          dgram = b'#bundle\x00'
          try:
              dgram += osc_types.write_date(self._timestamp)
              for content in self._contents:
                  if (type(content) == osc_message.OscMessage
                          or type(content) == osc_bundle.OscBundle):
                      size = content.size
                      dgram += osc_types.write_int(size)
                      dgram += content.dgram
                  else:
                      raise BuildError(
                          "Content must be either OscBundle or OscMessage"
                          "found {}".format(type(content)))
              return osc_bundle.OscBundle(dgram)
          except osc_types.BuildError as be:
              raise BuildError('Could not build the bundle {}'.format(be))
  
new_contents: """Build OSC bundles for client applications."""
  
  from pythonosc import osc_bundle
  from pythonosc import osc_message
  from pythonosc.parsing import osc_types
  
  # Shortcut to specify an immediate execution of messages in the bundle.
  IMMEDIATELY = osc_types.IMMEDIATELY
  
  
  class BuildError(Exception):
      """Error raised when an error occurs building the bundle."""
  
  
  class OscBundleBuilder(object):
      """Builds arbitrary OscBundle instances."""
  
      def __init__(self, timestamp: int) -> None:
          """Build a new bundle with the associated timestamp.
  
          Args:
            - timestamp: system time represented as a floating point number of
                         seconds since the epoch in UTC or IMMEDIATELY.
          """
          self._timestamp = timestamp
          self._contents = []
  
      def add_content(self, content: osc_bundle.OscBundle) -> None:
          """Add a new content to this bundle.
  
          Args:
            - content: Either an OscBundle or an OscMessage
          """
          self._contents.append(content)
  
      def build(self) -> osc_bundle.OscBundle:
          """Build an OscBundle with the current state of this builder.
  
          Raises:
            - BuildError: if we could not build the bundle.
          """
          dgram = b'#bundle\x00'
          try:
              dgram += osc_types.write_date(self._timestamp)
              for content in self._contents:
                  if (type(content) == osc_message.OscMessage
                          or type(content) == osc_bundle.OscBundle):
                      size = content.size
                      dgram += osc_types.write_int(size)
                      dgram += content.dgram
                  else:
                      raise BuildError(
                          "Content must be either OscBundle or OscMessage"
                          "found {}".format(type(content)))
              return osc_bundle.OscBundle(dgram)
          except osc_types.BuildError as be:
              raise BuildError('Could not build the bundle {}'.format(be))
  
subject: Add type annotation