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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 prepare_video_params(self, title=None, tags='Others', description='', copyright_type='original', public_type='all', category=None, watch_password=None, latitude=None, longitude=None, shoot_time=None ):
 """ util method for create video params to upload. Only need to provide a minimum of two essential parameters: title and tags, other video params are optional. All params spec see: http://cloud.youku.com/docs?id=110#create . Args: title: string, 2-50 characters. tags: string, 1-10 tags joind with comma. description: string, less than 2000 characters. copyright_type: string, 'original' or 'reproduced' public_type: string, 'all' or 'friend' or 'password' watch_password: string, if public_type is password. latitude: double. longitude: double. shoot_time: datetime. Returns: dict params that upload/create method need. """

        params = {}
        if title is None:
            title = self.file_name
        elif len(title) > 80:
            title = title[:80]

        if len(description) > 2000:
            description = description[0:2000]

        params['title'] = title
        params['tags'] = tags
        params['description'] = description
        params['copyright_type'] = copyright_type
        params['public_type'] = public_type
        if category:
            params['category'] = category
        if watch_password:
            params['watch_password'] = watch_password
        if latitude:
            params['latitude'] = latitude
        if longitude:
            params['longitude'] = longitude
        if shoot_time:
            params['shoot_time'] = shoot_time

        return params