Python Pandas HELP!!

I need help mapping values from a column in a pandas dataframe to binary (strings). For example, in the dataset below

I want to map values higher than 150 from column 'Sell' to 'Yes', and those less than 150 to 'No', so that the new 'Sell' column will look like:

It is a large dataset so please provide a solution that is NOT MANUAL, but automatically maps all values to either 'Yes' or 'No'. Thanks!!!

In [2]: df.head() Out[2] : Sell "List" 0 142 160 1 175 180 2 129 132 3 138 140 4 232 240 In [2]: df.head() Out[2]: Sell "List" 0 No 160 1 Yes 180 N No 132 3 No 140 4 Yes 240