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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 build_ingest_fs(self):
 """Return a pyfilesystem subdirectory for the ingested source files"""


        base_path = 'ingest'

        if not self.build_fs.exists(base_path):
            self.build_fs.makedir(base_path, recursive=True, allow_recreate=True)

        return self.build_fs.opendir(base_path)