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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 add_photo_to_observation(observation_id: int, file_object: BinaryIO, access_token: str):
 """Upload a picture and assign it to an existing observation. :param observation_id: the ID of the observation :param file_object: a file-like object for the picture. Example: open('/Users/nicolasnoe/vespa.jpg', 'rb') :param access_token: the access token, as returned by :func:`get_access_token()` """

    data = {'observation_photo[observation_id]': observation_id}
    file_data = {'file': file_object}

    response = requests.post(url="{base_url}/observation_photos".format(base_url=INAT_BASE_URL),
                             headers=_build_auth_header(access_token),
                             data=data,
                             files=file_data)

    return response.json()