There are two forms of expression input. Both ignore leading whitespace.
The string argument to eval() must have the following form:
eval_input: condition_list NEWLINE*
The input line read by input() must have the following form:
input_input: condition_list NEWLINE
Note: to read `raw' input line without interpretation, you can use the
built-in function raw_input() or the readline() method
of file objects.