slicing with .loc in pandas

Question

I was reading the book - "Python for Data Analysis" and doing code side-by-side on Jupiter notebook. Here is my DataFrame named data :

                 one    three   four
       Ohio       0       2      3
       Colorado   4       6      7
       Utah       8       10    11
       New York   12      14    15

and I used : data.loc[:"one"]. It gives a Keyerror 'one'.
But when I use: data.loc[:"Utah" , "one"]. It doesn't give any error. Can anyone tell me what's going one here.
So the problem is solved.
The error was I was missing a comma(,). I have to do something like this :

data.loc[:,"one"]

but i was doing data.loc[:"one"] which gave error. But we don't have to include "," while we are dealing with more than one column or it will give error( kind of weird syntax ).
eg : do this : data.loc[:"Utah","one"]
not this : data.loc[:,"Utah","one"]