def validate(self):
if self.access_token is None:<EOL><INDENT>raise ConfigurationError('<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>')<EOL><DEDENT>if re.search(r'<STR_LIT>', self.access_token):<EOL><INDENT>raise ConfigurationError('<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>')<EOL><DEDENT>if len(self.access_token) != <NUM_LIT:64>:<EOL><INDENT>raise ConfigurationError('<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>')<EOL><DEDENT>if not self.base_url or not re.match(self.URL_REGEXP, self.base_url):<EOL><INDENT>raise ConfigurationError('<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>')<EOL><DEDENT>return True<EOL>
Validates whether a configuration is valid.

        :rtype: bool
        :raises ConfigurationError: if no ``access_token`` provided.
        :raises ConfigurationError: if provided ``access_token`` is invalid - contains disallowed characters.
        :raises ConfigurationError: if provided ``access_token`` is invalid - has invalid length.
        :raises ConfigurationError: if provided ``base_url`` is invalid.