class BoundField

    def _has_changed(self):
        field = self.field
        if field.show_hidden_initial:
            hidden_widget = field.hidden_widget()
            initial_value = self.form._widget_data_value(
                hidden_widget,
                self.html_initial_name,
            )
            try:
                initial_value = field.to_python(initial_value)
            except ValidationError:
                # Always assume data has changed if validation fails.
                return True
        else:
            initial_value = self.initial
        return field.has_changed(initial_value, self.data)

    def as_field_group(self):
        return self.render()

    def as_text(self, attrs=None, **kwargs):
        """
        Return a string of HTML for representing this as an
        <input type="text">.
        """
        return self.as_widget(TextInput(), attrs, **kwargs)

    def as_textarea(self, attrs=None, **kwargs):
        """Return a string of HTML for representing this as a <textarea>."""
        return self.as_widget(Textarea(), attrs, **kwargs)

    def build_widget_attrs(self, attrs, widget=None):
        widget = widget or self.field.widget
        attrs = dict(attrs)  # Copy attrs to avoid modifying the argument.
        if (
            widget.use_required_attribute(self.initial)
            and self.field.required
            and self.form.use_required_attribute
        ):
            # MultiValueField has require_all_fields: if False, fall back
            # on subfields.
            if (
                hasattr(self.field, "require_all_fields")
                and not self.field.require_all_fields
                and isinstance(self.field.widget, MultiWidget)
            ):
                for subfield, subwidget in zip(self.field.fields, widget.widgets):
                    subwidget.attrs["required"] = (
                        subwidget.use_required_attribute(self.initial)
                        and subfield.required
                    )
            else:
                attrs["required"] = True
        if self.field.disabled:
            attrs["disabled"] = True
        if not widget.is_hidden and self.errors:
            attrs["aria-invalid"] = "true"
        # Preserve aria-describedby provided by the attrs argument so user
        # can set the desired order.
        if not attrs.get("aria-describedby") and not self.use_fieldset:
            if aria_describedby := self.aria_describedby:
                attrs["aria-describedby"] = aria_describedby
        return attrs

    def css_classes(self, extra_classes=None):
        """
        Return a string of space-separated CSS classes for this field.
        """
        if hasattr(extra_classes, "split"):
            extra_classes = extra_classes.split()
        extra_classes = set(extra_classes or [])
        if self.errors and hasattr(self.form, "error_css_class"):
            extra_classes.add(self.form.error_css_class)
        if self.field.required and hasattr(self.form, "required_css_class"):
            extra_classes.add(self.form.required_css_class)
        return " ".join(extra_classes)

    def label_tag(self, contents=None, attrs=None, label_suffix=None, tag=None):
        """
        Wrap the given contents in a <label>, if the field has an ID attribute.
        contents should be mark_safe'd to avoid HTML escaping. If contents
        aren't given, use the field's HTML-escaped label.

        If attrs are given, use them as HTML attributes on the <label> tag.

        label_suffix overrides the form's label_suffix.
        """
        contents = contents or self.label
        if label_suffix is None:
            label_suffix = (
                self.field.label_suffix
                if self.field.label_suffix is not None
                else self.form.label_suffix
            )
        # Only add the suffix if the label does not end in punctuation.
        # Translators: If found as last label character, these punctuation
        # characters will prevent the default label_suffix to be appended to
        # the label
        if label_suffix and contents and contents[-1] not in _(":?.!"):
            contents = format_html("{}{}", contents, label_suffix)
        widget = self.field.widget
        id_ = widget.attrs.get("id") or self.auto_id
        if id_:
            id_for_label = widget.id_for_label(id_)
            if id_for_label:
                attrs = {**(attrs or {}), "for": id_for_label}
            if self.field.required and hasattr(self.form, "required_css_class"):
                attrs = attrs or {}
                if "class" in attrs:
                    attrs["class"] += " " + self.form.required_css_class
                else:
                    attrs["class"] = self.form.required_css_class
        context = {
            "field": self,
            "label": contents,
            "attrs": attrs,
            "use_tag": bool(id_),
            "tag": tag or "label",
        }
        return self.form.render(self.form.template_name_label, context)

    def legend_tag(self, contents=None, attrs=None, label_suffix=None):
        """
        Wrap the given contents in a <legend>, if the field has an ID
        attribute. Contents should be mark_safe'd to avoid HTML escaping. If
        contents aren't given, use the field's HTML-escaped label.

        If attrs are given, use them as HTML attributes on the <legend> tag.

        label_suffix overrides the form's label_suffix.
        """
        return self.label_tag(contents, attrs, label_suffix, tag="legend")

    def render(self, template_name=None, context=None, renderer=None):
        renderer = renderer or self.renderer
        template = template_name or self.template_name
        context = context or self.get_context()
        return mark_safe(renderer.render(template, context))

    def value(self):
        """
        Return the value for this BoundField, using the initial value if
        the form is not bound or the data otherwise.
        """
        data = self.initial
        if self.form.is_bound:
            data = self.field.bound_data(self.data, data)
        return self.field.prepare_value(data)