I have a dataframe:

```
Color   Name    Age   City   Value
Blue    Bob     28    Atl    0
Green   Bob     27    Chi    0
Blue    Sam     28    Atl    0

```

I have the above DF and I want all values to equal 1 if the color is blue, age is 28 and city is Atl.

I tried using df.loc but I got an error that says 'too many indexers'