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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 upload(self, local_fn: str, remote_fn: str = '', dont_overwrite: bool = False):
 """Uploads given file to the task. If remote_fn is not specified, dumps it into task current directory with the same name. Args: local_fn: location of file locally remote_fn: location of file on task dont_overwrite: if True, will be no-op if target file exists """

    raise NotImplementedError()