How to use the libcst._nodes.internal.visit_optional function in libcst

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "AnnAssign":
        return AnnAssign(
            target=visit_required(self, "target", self.target, visitor),
            annotation=visit_required(self, "annotation", self.annotation, visitor),
            equal=visit_sentinel(self, "equal", self.equal, visitor),
            value=visit_optional(self, "value", self.value, visitor),
            semicolon=visit_sentinel(self, "semicolon", self.semicolon, visitor),
        )

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "While":
        return While(
            leading_lines=visit_sequence(
                self, "leading_lines", self.leading_lines, visitor
            ),
            whitespace_after_while=visit_required(
                self, "whitespace_after_while", self.whitespace_after_while, visitor
            ),
            test=visit_required(self, "test", self.test, visitor),
            whitespace_before_colon=visit_required(
                self, "whitespace_before_colon", self.whitespace_before_colon, visitor
            ),
            body=visit_required(self, "body", self.body, visitor),
            orelse=visit_optional(self, "orelse", self.orelse, visitor),
        )

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "Param":
        return Param(
            star=self.star,
            whitespace_after_star=visit_required(
                self, "whitespace_after_star", self.whitespace_after_star, visitor
            ),
            name=visit_required(self, "name", self.name, visitor),
            annotation=visit_optional(self, "annotation", self.annotation, visitor),
            equal=visit_sentinel(self, "equal", self.equal, visitor),
            default=visit_optional(self, "default", self.default, visitor),
            comma=visit_sentinel(self, "comma", self.comma, visitor),
            whitespace_after_param=visit_required(
                self, "whitespace_after_param", self.whitespace_after_param, visitor
            ),

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "Raise":
        return Raise(
            whitespace_after_raise=visit_sentinel(
                self, "whitespace_after_raise", self.whitespace_after_raise, visitor
            ),
            exc=visit_optional(self, "exc", self.exc, visitor),
            cause=visit_optional(self, "cause", self.cause, visitor),
            semicolon=visit_sentinel(self, "semicolon", self.semicolon, visitor),
        )

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "EmptyLine":
        return EmptyLine(
            indent=self.indent,
            whitespace=visit_required(self, "whitespace", self.whitespace, visitor),
            comment=visit_optional(self, "comment", self.comment, visitor),
            newline=visit_required(self, "newline", self.newline, visitor),
        )

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "Slice":
        return Slice(
            lower=visit_optional(self, "lower", self.lower, visitor),
            first_colon=visit_required(self, "first_colon", self.first_colon, visitor),
            upper=visit_optional(self, "upper", self.upper, visitor),
            second_colon=visit_sentinel(
                self, "second_colon", self.second_colon, visitor
            ),
            step=visit_optional(self, "step", self.step, visitor),
        )

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "ImportFrom":
        names = self.names
        return ImportFrom(
            whitespace_after_from=visit_required(
                self, "whitespace_after_from", self.whitespace_after_from, visitor
            ),
            relative=visit_sequence(self, "relative", self.relative, visitor),
            module=visit_optional(self, "module", self.module, visitor),
            whitespace_before_import=visit_required(
                self, "whitespace_before_import", self.whitespace_before_import, visitor
            ),
            whitespace_after_import=visit_required(
                self, "whitespace_after_import", self.whitespace_after_import, visitor
            ),
            lpar=visit_optional(self, "lpar", self.lpar, visitor),
            names=(
                visit_required(self, "names", names, visitor)
                if isinstance(names, ImportStar)
                else visit_sequence(self, "names", names, visitor)
            ),
            rpar=visit_optional(self, "rpar", self.rpar, visitor),
            semicolon=visit_sentinel(self, "semicolon", self.semicolon, visitor),
        )

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "Try":
        return Try(
            leading_lines=visit_sequence(
                self, "leading_lines", self.leading_lines, visitor
            ),
            whitespace_before_colon=visit_required(
                self, "whitespace_before_colon", self.whitespace_before_colon, visitor
            ),
            body=visit_required(self, "body", self.body, visitor),
            handlers=visit_sequence(self, "handlers", self.handlers, visitor),
            orelse=visit_optional(self, "orelse", self.orelse, visitor),
            finalbody=visit_optional(self, "finalbody", self.finalbody, visitor),
        )

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "ImportAlias":
        return ImportAlias(
            name=visit_required(self, "name", self.name, visitor),
            asname=visit_optional(self, "asname", self.asname, visitor),
            comma=visit_sentinel(self, "comma", self.comma, visitor),
        )

def _visit_and_replace_children(self, visitor: CSTVisitorT) -> "Try":
        return Try(
            leading_lines=visit_sequence(
                self, "leading_lines", self.leading_lines, visitor
            ),
            whitespace_before_colon=visit_required(
                self, "whitespace_before_colon", self.whitespace_before_colon, visitor
            ),
            body=visit_required(self, "body", self.body, visitor),
            handlers=visit_sequence(self, "handlers", self.handlers, visitor),
            orelse=visit_optional(self, "orelse", self.orelse, visitor),
            finalbody=visit_optional(self, "finalbody", self.finalbody, visitor),
        )