fix mypy

Author: tswast

bigframes/core/compile/ibis_compiler/default_ordering.py

@@ -47,10 +47,7 @@ def _convert_to_nonnull_string(column: ibis_types.Value) -> ibis_types.StringVal
         result = ibis_ops.ToJsonString(column).to_expr()  # type: ignore
     # Escape backslashes and use backslash as delineator
     escaped = cast(
-        ibis_types.StringColumn,
-        result.fill_null(ibis_types.literal(""))
-        if hasattr(result, "fill_null")
-        else result.fill_null(""),
+        ibis_types.StringColumn, result.fill_null(ibis_types.literal(""))
     ).replace(
         "\\",  # type: ignore
         "\\\\",  # type: ignore

bigframes/core/compile/ibis_compiler/scalar_op_registry.py

@@ -1064,7 +1064,7 @@ def isin_op_impl(x: ibis_types.Value, op: ops.IsInOp):
     if op.match_nulls and contains_nulls:
         return x.isnull() | x.isin(matchable_ibis_values)
     else:
-        return x.isin(matchable_ibis_values).fill_null(False)
+        return x.isin(matchable_ibis_values).fill_null(ibis.literal(False))
 
 
 @scalar_op_compiler.register_unary_op(ops.ToDatetimeOp, pass_op=True)