I'm trying to add key-value pairs to a dictionary by pairing two and two lines from a text file. Why does this not work?

```
newdata = {}
os.chdir("//GOLLUM//tbg2//tbg2//forritGB")
f = open(filename)
for line1, line2 in f.readlines():
    newdata[line1] = line2

```

edit: The error I get is

```
ValueError: too many values to unpack

```