Unique list of dictionaries

unique_dicts.py

# unique list of dictionaries
# ---------------------------
# This problem comes up when I bulk insert records into databases
# because I can't check for existence of records (they don't exist yet, too slow, etc)
#
# I typically use a set to make list elements unique, but dicts and lists themselves
# can't be inserted in sets because they're mutable and thus unhashable.
#
# Solution is to make a tuple of the dict's items and insert it in set,
# then create dicts from each member of the set.

_set = set()
w = dict(a=2,b=3,c=4)
x = dict(a=6,b=4,c=2)
y = dict(c=4,a=2,b=3)
z = dict(b=7,c=8,a=9)

_set.add(tuple(w.items()))
_set.add(tuple(x.items()))
_set.add(tuple(y.items()))
_set.add(tuple(z.items()))

records = [dict(elements) for elements in _set]