Python 3.15+sysfunction

sys.set_lazy_imports_filter()

modules

Installs a filter that decides, for each import, whether it may be lazy. The filter receives module names and returns True or False; None removes it.

Syntax

sys.set_lazy_imports_filter(filter)

The filter is called with three positional arguments: the name of the importing module, the full name of the imported one (for lazy from .spam import eggs, package.spam) and fromlist, a tuple of names for a from-import or None. True allows laziness, False forces an immediate load. A typical use is the 'all' mode for your own modules only: the filter passes names starting with 'myapp.' while third-party dependencies load as usual. It is a tool for narrow cases; an ordinary program is fine with the lazy keyword.

Examples

import sys
def only_mine(importing, imported, fromlist):
    return imported.startswith('myapp.')
sys.set_lazy_imports_filter(only_mine)
print(sys.get_lazy_imports_filter() is only_mine)  # → True
sys.set_lazy_imports_filter(None)
print(sys.get_lazy_imports_filter())  # → None

See also

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