def stolpec_prost(stolpec,razpored):
    for i in razpored:
        if stolpec == i[0]:
            return False
    else:
        return True


def prosti_stolpci(razpored):
    zasedeni=[]
    for x in razpored:
        zasedeni.append(x[0])
    prosti = []
    print (zasedeni)
    for y in "abcdefgh":
        if y != zasedeni:
            prosti.append(y)
    return prosti



stolpci = "abcdefgh"
vrstice = "12345678"

print (stolpec_prost("b",["a4", "c7", "d2"]))
print (prosti_stolpci(["a4", "c7", "d2"]))