gistfile1.py

import ast

node = ast.Expression(ast.BinOp(left=ast.Num(5, lineno=0, col_offset=0),
                                op=ast.Add(),
                                right=ast.Num(2, lineno=0, col_offset=0),
                                lineno=0,
                                col_offset=0),
                      lineno=0,
                      col_offset=0)

print eval(compile(ast.parse(node), '<string>', mode='eval'))