<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def create(self, friendly_name, available=values.unset):
 """ Create a new ActivityInstance :param unicode friendly_name: A human-readable name for the Activity, such as 'On Call', 'Break', 'Email', etc. :param bool available: Boolean value indicating whether the worker should be eligible to receive a Task when they occupy this Activity. :returns: Newly created ActivityInstance :rtype: twilio.rest.taskrouter.v1.workspace.activity.ActivityInstance """

        data = values.of({'FriendlyName': friendly_name, 'Available': available, })

        payload = self._version.create(
            'POST',
            self._uri,
            data=data,
        )

        return ActivityInstance(self._version, payload, workspace_sid=self._solution['workspace_sid'], )