Same format than *requires-dist*. *optional*, *multi*, *environ*
requires-python
- Specifies the Python version the distribution requires.
- The value is a version number, as described in PEP 345.
- *optional*, *multi*, *environ*
+ Specifies the Python version the distribution requires. The value is a
+ comma-separated list of version predicates, as described in PEP 345.
+ *optional*, *environ*
requires-externals
a dependency in the system. This field is free-form,