Flatten list without using stdlib function

flatten.py

import unittest

def flatten(l):
	collect = []
	# make user l is iterable of some sort and not a dictionary
	if hasattr(l, '__iter__') and not isinstance(l, dict):
		for e in l:
			print e
			print flatten(e)
			collect += flatten(e)
	else:
		collect.append(l)
	return collect


class TestFlatten(unittest.TestCase):
	def testSimple(self):
		self.assertEqual(flatten([1,2,3,[4]]), [1,2,3,4])
	def testSingle(self):
		self.assertEqual(flatten(0), [0])

	def testMapinList(self):
		self.assertEqual(flatten([1, [{'m':'m'}]]), [1, {'m':'m'}])


if __name__ == '__main__':
	unittest.main()