Support for lazy import

[tobiasdiez]

Is your feature request related to a problem? Please describe.
In some situations, it is better to lazy import a module. For example, in sage this is via lazy_import('sage.rings.all', 'RDF', 'my_RDF') in place of the standard import ... from ... as ... syntax, see https://doc.sagemath.org/html/en/reference/misc/sage/misc/lazy_import.html.
Pyright currently does not pick up these imports and warns that the class is unknown (my_RDF in the above example).

Describe the solution you'd like
Properly recognize lazy imports.

[erictraut]

There's currently no support in the Python standard for expressing lazy imports. Pyright follows the Python standard and does not contain any special knowledge of third-party library behaviors like the one in sage.

As a workaround, you could use lazy imports in conjunction with traditional imports, but place the traditional imports within a if TYPE_CHECKING: statement. That way, it won't execute at runtime, but the type checker will know about import for type checking purposes.

[tobiasdiez]

Thanks!