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Because bytecode is platform-independent (due to being run through the platform's interpreter), Python code can be released either as .py source files or as .pyc bytecode. This is where bytecode-only packages come into play; to provide a bit of obfuscation and (subjective) security, Python programs can be released without the source code and only the pre-compiled .pyc files are provided. In this case, the compiled code is placed in the source directory rather than the source-code files.