How to use the cssselect.parser.SelectorError function in cssselect

if sys.version_info[0] < 3:
    _basestring = basestring
    _unicode = unicode
else:
    _basestring = str
    _unicode = str


def _unicode_safe_getattr(obj, name, default=None):
    # getattr() with a non-ASCII name fails on Python 2.x
    name = name.encode('ascii', 'replace').decode('ascii')
    return getattr(obj, name, default)


class ExpressionError(SelectorError, RuntimeError):
    """Unknown or unsupported selector (eg. pseudo-class)."""


#### XPath Helpers

class XPathExpr(object):

    def __init__(self, path='', element='*', condition='', star_prefix=False):
        self.path = path
        self.element = element
        self.condition = condition

    def __str__(self):
        path =  _unicode(self.path) + _unicode(self.element)
        if self.condition:
            path += '[%s]' % self.condition

import sys
import re

from cssselect.parser import parse, parse_series, SelectorError


if sys.version_info[0] < 3:
    _basestring = basestring
    _unicode = unicode
else:
    _basestring = str
    _unicode = str


class ExpressionError(SelectorError, RuntimeError):
    """Unknown or unsupported selector (eg. pseudo-class)."""


#### XPath Helpers

class XPathExpr(object):

    def __init__(self, path='', element='*', condition='', star_prefix=False):
        self.path = path
        self.element = element
        self.condition = condition

    def __str__(self):
        path =  _unicode(self.path) + _unicode(self.element)
        if self.condition:
            path += '[%s]' % self.condition

if sys.version_info[0] < 3:
    _basestring = basestring
    _unicode = unicode
else:
    _basestring = str
    _unicode = str


def _unicode_safe_getattr(obj, name, default=None):
    # getattr() with a non-ASCII name fails on Python 2.x
    name = name.encode('ascii', 'replace').decode('ascii')
    return getattr(obj, name, default)


class ExpressionError(SelectorError, RuntimeError):
    """Unknown or unsupported selector (eg. pseudo-class)."""


#### XPath Helpers

class XPathExpr(object):

    def __init__(self, path='', element='*', condition='', star_prefix=False):
        self.path = path
        self.element = element
        self.condition = condition

    def __str__(self):
        path =  _unicode(self.path) + _unicode(self.element)
        if self.condition:
            path += '[%s]' % self.condition