I have working code. My question is *why* does this work?

```
#"04/13/05 2:30pm EDT" <- original date string
from datetime import datetime, timedelta
from pytz import timezone
import pytz
import time

T= time.struct_time((2005,4,13,14,30,0,0,0,1))
t = time.mktime(T)

print(t)

```

this prints 

```
1113417000, 

```

which according to an online converter, <http://www.epochconverter.com/>, prints

```
Your time zone: 4/13/2005 2:30:00 PM GMT-4

```

which is correct. My question is, how does it know the time was in EDT which is GMT-4? The last of the 9-tuple is "dst flag", but there are numerous timezones where DST is used. So how does it detect the correct timezone?