def unique_column_values(rows, column_name):
    """
    Given a list of rows and the name of a column (a string), returns a set
    containing all values in that column.
    """
    column = []
    for row in rows:
        column.append(row.get(column_name)) 	#Store the column data for each row and store in the list

    set1 = set(column)				#Set() to get unique values
    return set1