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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def setup(self, # pylint: disable=arguments-differ endpoint=None, username=None, password=None, incident_id=None, sketch_id=None):
 """Setup a connection to a Timesketch server and create a sketch if needed. Args: endpoint: str, Timesketch endpoint (e.g. http://timesketch.com/) username: str, Username to authenticate against the Timesketch endpoint. password: str, Password to authenticate against the Timesketch endpoint. incident_id: str, Incident ID or reference. Used in sketch description. sketch_id: int, Sketch ID to add the resulting timeline to. If not provided, a new sketch is created. """

    self.timesketch_api = timesketch_utils.TimesketchApiClient(
        endpoint, username, password)
    self.incident_id = None
    self.sketch_id = int(sketch_id) if sketch_id else None

    # Check that we have a timesketch session
    if not self.timesketch_api.session:
      message = 'Could not connect to Timesketch server at ' + endpoint
      self.state.add_error(message, critical=True)
      return

    if not self.sketch_id:  # No sketch id is provided, create it
      if incident_id:
        sketch_name = 'Sketch for incident ID: ' + incident_id
      else:
        sketch_name = 'Untitled sketch'
      sketch_description = 'Sketch generated by dfTimewolf'

      self.sketch_id = self.timesketch_api.create_sketch(
          sketch_name, sketch_description)
      print('Sketch {0:d} created'.format(self.sketch_id))