>>> code="""a=1
... print a"""
>>> code
'a=1\nprint a'
>>> compile(code,'<string>','exec')
<code object <module> at 0xb77065c0, file "<string>", line 1>
>>> exec(_,{"a":3})
1
>>> exec(_,{"a":3},{"a":4})
1
>>> code="print a"
>>> compile(code,'<string>','exec')
<code object <module> at 0xb7706a40, file "<string>", line 1>
>>> exec(_,{"a":3},{"a":4})
4
>>>
