Control how the generated byte-code files are invalidated at runtime. The
timestamp value, means that
.pyc files with the source timestamp and size embedded will be generated. The
unchecked-hash values cause hash-based pycs to be generated. Hash-based pycs embed a hash of the source file contents rather than a timestamp. See Cached bytecode invalidation for more information on how Python validates bytecode cache files at runtime. The default is
timestamp if the
SOURCE_DATE_EPOCH environment variable is not set, and
checked-hash if the
SOURCE_DATE_EPOCH environment variable is set.