class_docstr: Utility class for the `when-then-otherwise` expression.
  
  Represents the state of the expression after `pl.when(...).then(...)` is called.
class_docstr_tok: ["Utility","class","for","the","`","when-then-otherwise","`","expression",".","Represents","the","state","of","the","expression","after","`","pl.when","(","...",")",".then","(","...",")","`","is","called","."]
code: def _pyexpr(self) -> PyExpr:
      return self._then.otherwise(F.lit(None)._pyexpr)
  
imports: from __future__ import annotations
  from typing import TYPE_CHECKING, Any, Iterable
  import polars.functions
  from polars.expr.expr import Expr
  from polars.utils._parse_expr_input import parse_as_expression, parse_when_constraint_expressions
  from polars.utils._wrap import wrap_expr
label_desc: Use image node_id 3 for calling the Then obj's underlying member method code with example usage: obj._pyexpr() and returns: self