Counting characters in a string putting them in a dictionary

counting_string

import sys
import unittest

def count(text):

	# if the text is None or empty do nothing
	if text: 
		text = text.replace(' ', '')
	else:
		return None

	# count the element.
	counter = {}
	for c in text:
		if not c in counter:
			counter[c] = text.count(c)

	return counter


class TestCount(unittest.TestCase):

	def setUp(self):
		pass

	def test_none_str(self):

		self.assertEqual(count(None), None)

	def test_empty_str(self):

		self.assertEqual(count(''), None)	

	def test_empty_blank(self):

		self.assertEqual(count(' '), {})

	def test_count(self):

		self.assertEqual(count('abbcccdddd'), {'a':1, 'b':2, 'c':3, 'd':4})


if __name__ == '__main__':

	try:
		text = sys.argv[1]

		counter = count(text)

		if counter:
			for key in sorted(counter.iterkeys()):
				print "%s %s" % (key, counter[key])

	except IndexError:
		print 'Missed text.'