Issue 29310: Document typing.NamedTuple default argument syntax
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@ -735,10 +735,21 @@ The module defines the following classes, functions and decorators:
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Employee = collections.namedtuple('Employee', ['name', 'id'])
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The resulting class has one extra attribute: ``_field_types``,
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giving a dict mapping field names to types. (The field names
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are in the ``_fields`` attribute, which is part of the namedtuple
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API.)
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To give a field a default value, you can assign to it in the class body::
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class Employee(NamedTuple):
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name: str
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id: int = 3
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employee = Employee('Guido')
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assert employee.id == 3
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Fields with a default value must come after any fields without a default.
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The resulting class has two extra attributes: ``_field_types``,
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giving a dict mapping field names to types, and ``field_defaults``, a dict
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mapping field names to default values. (The field names are in the
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``_fields`` attribute, which is part of the namedtuple API.)
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Backward-compatible usage::
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@ -747,6 +758,9 @@ The module defines the following classes, functions and decorators:
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.. versionchanged:: 3.6
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Added support for :pep:`526` variable annotation syntax.
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.. versionchanged:: 3.6.1
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Added support for default values.
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.. function:: NewType(typ)
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A helper function to indicate a distinct types to a typechecker,
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