"""Returns a string that describes the shape of a data structure.

typename = type(ds).__name__

# handle sequences

sequence = (list, tuple, set, type(iter('')))

if isinstance(ds, sequence):

t = []

for i, x in enumerate(ds):

t.append(structshape(x))

rep = '%s of %s' % (typename, listrep(t))

return rep

# handle dictionaries

elif isinstance(ds, dict):

keys = set()

vals = set()

for k, v in ds.items():

keys.add(structshape(k))

vals.add(structshape(v))

rep = '%s of %d %s->%s' % (typename, len(ds),

setrep(keys), setrep(vals))

return rep

# handle other types

else:

if hasattr(ds, '__class__'):

return ds.__class__.__name__

else:

"""Returns a string representation of a list of type strings.

current = t[0]

count = 0

res = []

for x in t:

if x == current:

count += 1

else:

append(res, current, count)

current = x

count = 1

append(res, current, count)

"""Returns a string representation of a set of type strings.

rep = ', '.join(s)

if len(s) == 1:

return rep

else:

return '(' + rep + ')'

"""Adds a new element to a list of type strings.

if count == 1:

rep = typestr

else:

rep = '%d %s' % (count, typestr)