def __getitem__(self, name):
<EOL>if name not in self._data:<EOL><INDENT>raise KeyError(name)<EOL><DEDENT>if name in self._special:<EOL><INDENT>return self._special[name]<EOL><DEDENT>return self._data[name]<EOL>
Retrieve the value of a variable from the environment.  If the
variable has been declared as a list-like variable, the return
value will be a list of strings; otherwise, it will be a
string.

:param name: The name of the variable to retrieve.

:returns: The value of the designated variable.