How to use the bs4.element.whitespace_re.split function in bs4

Modifies its input in place.
        """
        if not attrs:
            return attrs
        if self.cdata_list_attributes:
            universal = self.cdata_list_attributes.get('*', [])
            tag_specific = self.cdata_list_attributes.get(
                tag_name.lower(), None)
            for attr in attrs.keys():
                if attr in universal or (tag_specific and attr in tag_specific):
                    # We have a "class"-type attribute whose string
                    # value is a whitespace-separated list of
                    # values. Split it into a list.
                    value = attrs[attr]
                    if isinstance(value, basestring):
                        values = whitespace_re.split(value)
                    else:
                        # html5lib sometimes calls setAttributes twice
                        # for the same tag when rearranging the parse
                        # tree. On the second call the attribute value
                        # here is already a list.  If this happens,
                        # leave the value alone rather than trying to
                        # split it again.
                        values = value
                    attrs[attr] = values
        return attrs

Modifies its input in place.
        """
        if not attrs:
            return attrs
        if self.cdata_list_attributes:
            universal = self.cdata_list_attributes.get('*', [])
            tag_specific = self.cdata_list_attributes.get(
                tag_name.lower(), None)
            for attr in attrs.keys():
                if attr in universal or (tag_specific and attr in tag_specific):
                    # We have a "class"-type attribute whose string
                    # value is a whitespace-separated list of
                    # values. Split it into a list.
                    value = attrs[attr]
                    if isinstance(value, basestring):
                        values = whitespace_re.split(value)
                    else:
                        # html5lib sometimes calls setAttributes twice
                        # for the same tag when rearranging the parse
                        # tree. On the second call the attribute value
                        # here is already a list.  If this happens,
                        # leave the value alone rather than trying to
                        # split it again.
                        values = value
                    attrs[attr] = values
        return attrs

def __setitem__(self, name, value):
        # If this attribute is a multi-valued attribute for this element,
        # turn its value into a list.
        list_attr = HTML5TreeBuilder.cdata_list_attributes
        if (name in list_attr['*']
            or (self.element.name in list_attr
                and name in list_attr[self.element.name])):
            # A node that is being cloned may have already undergone
            # this procedure.
            if not isinstance(value, list):
                value = whitespace_re.split(value)
        self.element[name] = value
    def items(self):

def __setitem__(self, name, value):
        # If this attribute is a multi-valued attribute for this element,
        # turn its value into a list.
        list_attr = HTML5TreeBuilder.cdata_list_attributes
        if (name in list_attr['*']
            or (self.element.name in list_attr
                and name in list_attr[self.element.name])):
            # A node that is being cloned may have already undergone
            # this procedure.
            if not isinstance(value, list):
                value = whitespace_re.split(value)
        self.element[name] = value
    def items(self):

"""Replaces class="foo bar" with class=["foo", "bar"]

        Modifies its input in place.
        """
        if self.cdata_list_attributes:
            universal = self.cdata_list_attributes.get('*', [])
            tag_specific = self.cdata_list_attributes.get(
                tag_name.lower(), [])
            for cdata_list_attr in itertools.chain(universal, tag_specific):
                if cdata_list_attr in attrs:
                    # Basically, we have a "class" attribute whose
                    # value is a whitespace-separated list of CSS
                    # classes. Split it into a list.
                    value = attrs[cdata_list_attr]
                    if isinstance(value, basestring):
                        values = whitespace_re.split(value)
                    else:
                        # html5lib sometimes calls setAttributes twice
                        # for the same tag when rearranging the parse
                        # tree. On the second call the attribute value
                        # here is already a list.  If this happens,
                        # leave the value alone rather than trying to
                        # split it again.
                        values = value
                    attrs[cdata_list_attr] = values
        return attrs

Modifies its input in place.
        """
        if not attrs:
            return attrs
        if self.cdata_list_attributes:
            universal = self.cdata_list_attributes.get('*', [])
            tag_specific = self.cdata_list_attributes.get(
                tag_name.lower(), None)
            for attr in attrs.keys():
                if attr in universal or (tag_specific and attr in tag_specific):
                    # We have a "class"-type attribute whose string
                    # value is a whitespace-separated list of
                    # values. Split it into a list.
                    value = attrs[attr]
                    if isinstance(value, basestring):
                        values = whitespace_re.split(value)
                    else:
                        # html5lib sometimes calls setAttributes twice
                        # for the same tag when rearranging the parse
                        # tree. On the second call the attribute value
                        # here is already a list.  If this happens,
                        # leave the value alone rather than trying to
                        # split it again.
                        values = value
                    attrs[attr] = values
        return attrs

def __setitem__(self, name, value):
        # If this attribute is a multi-valued attribute for this element,
        # turn its value into a list.
        list_attr = HTML5TreeBuilder.cdata_list_attributes
        if (name in list_attr['*']
            or (self.element.name in list_attr
                and name in list_attr[self.element.name])):
            # A node that is being cloned may have already undergone
            # this procedure.
            if not isinstance(value, list):
                value = whitespace_re.split(value)
        self.element[name] = value
    def items(self):

def __setitem__(self, name, value):
        # If this attribute is a multi-valued attribute for this element,
        # turn its value into a list.
        list_attr = HTML5TreeBuilder.cdata_list_attributes
        if (name in list_attr['*']
            or (self.element.name in list_attr
                and name in list_attr[self.element.name])):
            # A node that is being cloned may have already undergone
            # this procedure.
            if not isinstance(value, list):
                value = whitespace_re.split(value)
        self.element[name] = value
    def items(self):

Modifies its input in place.
        """
        if not attrs:
            return attrs
        if self.cdata_list_attributes:
            universal = self.cdata_list_attributes.get('*', [])
            tag_specific = self.cdata_list_attributes.get(
                tag_name.lower(), None)
            for attr in list(attrs.keys()):
                if attr in universal or (tag_specific and attr in tag_specific):
                    # We have a "class"-type attribute whose string
                    # value is a whitespace-separated list of
                    # values. Split it into a list.
                    value = attrs[attr]
                    if isinstance(value, str):
                        values = whitespace_re.split(value)
                    else:
                        # html5lib sometimes calls setAttributes twice
                        # for the same tag when rearranging the parse
                        # tree. On the second call the attribute value
                        # here is already a list.  If this happens,
                        # leave the value alone rather than trying to
                        # split it again.
                        values = value
                    attrs[attr] = values
        return attrs