def _stringify_value(self, value):
<EOL>if isinstance(value, (dict, list, tuple)) or value is None:<EOL><INDENT>result = self._BLANK_VALUE<EOL><DEDENT>elif value is True:<EOL><INDENT>result = "<STR_LIT:true>"<EOL><DEDENT>elif value is False:<EOL><INDENT>result = "<STR_LIT:false>"<EOL><DEDENT>elif sys.version_info.major > <NUM_LIT:2>:<EOL><INDENT>result = str(value)<EOL><DEDENT>elif not isinstance(value, unicode):  <EOL><INDENT>result = str(value)<EOL><DEDENT>else:<EOL><INDENT>result = value<EOL><DEDENT>return result<EOL>
This method stringifies values of environment variables. If the value of the method is a list or dictionary,
then this method will replace it with empty string. Values of environment variables in Lambda must be a string.
List or dictionary usually means they are intrinsic functions which have not been resolved.

:param value: Value to stringify
:return string: Stringified value