':return: True if the URL is vulnerable to SQL injection.'

def is_vulnerable(self):

    if self.verified_vulnerable:
        return self.verified_vulnerable
    params = ['--batch']
    (full_command, stdout, stderr) = self.run_sqlmap(params)
    if (full_command is None):
        return False
    if ((self.VULN_STR in stdout) and (self.NOT_VULN_STR not in stdout)):
        self.verified_vulnerable = True
        return True
    if ((self.NOT_VULN_STR in stdout) and (self.VULN_STR not in stdout)):
        return False
    for error_string in self.SQLMAP_ERRORS:
        if (error_string in stdout):
            return False
    fmt = 'Unexpected    answer    found    in    sqlmap    output    for    command    "%s":    "%s"'
    raise NotImplementedError((fmt % (full_command, stdout)))
