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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 get_webhook_url(deployment_name, space='default', data_source='webhook', token_manager=None, app_url=defaults.APP_URL, **fields):
 """ return the webhook URL for posting webhook data to """


    import_url = data_engine.get_import_data_url(deployment_name,
                                                 app_url=app_url,
                                                 token_manager=token_manager)

    api_key = deployments.get_apikey(deployment_name,
                                     token_manager=token_manager,
                                     app_url=app_url)

    fields_string = '&'.join(['%s=%s' % (key, value)
                              for (key, value) in fields.items()])
    return '%s/api/v1/import/webhook/?space=%s&data_source=%sk&apikey=%s&%s' % \
           (import_url, space, data_source, api_key, fields_string)