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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_file_size(path, get_retriever):
 """Return file size in megabytes, including querying remote integrations """

    integration, config = get_retriever.integration_and_config(path)
    if integration:
        return integration.file_size(path, config)
    elif os.path.exists(path):
        return os.path.getsize(path) / (1024.0 * 1024.0)