'''
Created on May 4, 2011

@author: ola
'''

def labify(attend):
    d = {}
    for stud in attend:
        for lab in attend[stud]:
            if lab not in d:
                d[lab] = []
            d[lab].append(stud)
            
    for lab in d:
        d[lab].sort()
    return d

labs = {
        "Fred" : ["lab1", "lab2", "lab4", "lab6"],
        "Ethel" : ["lab1","lab2", "lab3", "lab4", "lab5", "lab6"],
        "Alex" : ["lab3"],
        "Mary" : ["lab4", "lab3", "lab1", "lab6"]
        }

x = labify(labs)

print labs
print x