Desired capabilities error in Appium(1.5.3(ara)) using python(2.7)

{code}
import unittest, time, os
from appium import webdriver
from time import sleep
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
from selenium.webdriver import Android
#from .android.webdriver import WebDriver as Android
from numpy.distutils.fcompiler import none
from selenium.webdriver.opera.options import AndroidOptions
from appium.webdriver.webdriver import WebDriver
import appium
#import appium
#import
#from appium.webdriver.android.webdriver import WebDriver
desired_caps = DesiredCapabilities
class Android_Maaii(unittest.TestCase):
“Class to run tests against the ATP WTA app”

def setUp(self):

    
    desired_caps = {'platformName':'Android','platformVersion':'6.0.1','automationName':'Appium','deviceName':'Galaxy S4','appPackage':'com.android.vending','appActivity': '.AssetBrowserActivity'}
    print desired_caps
    if desired_caps is None:
        print "it can;t be none"
    print "its not none"
    self.driver= webdriver.Remote('http://127.0.0.1:4723/wd/hub',desired_caps) 
    print "i am here"
def tearDown(self): 
    print "here"
    "Tear down the test"
    self.AppiumDriver.quit()

def test_maaii(self):
    print "here2"
    #"Testing the ATP WTA app "
    self.AppiumDriver.implicitly_wait(30)
    
    time.sleep(5)

    print ("Slept for 5 sec...")

    element = self.AppiumDriver.find_element_by_name('7')

#—START OF SCRIPT
if name == ‘main’:
suite = unittest.TestLoader().loadTestsFromTestCase(Android_Maaii)

On above code i am getting below error. Please help me!!
Traceback (most recent call last):
File “/Users/manusimply/Desktop/Eclipse/CNN_PoC/Demo.py”, line 5, in
class Android_Maaii(unittest.TestCase):
File “/Users/manusimply/Desktop/Eclipse/CNN_PoC/Demo.py”, line 15, in Android_Maaii
setUp()
File “/Users/manusimply/Desktop/Eclipse/CNN_PoC/Demo.py”, line 10, in setUp
self.driver = webdriver.Android(‘http://127.0.0.1’,4723,desired_caps)
File “/Library/Python/2.7/site-packages/selenium/webdriver/android/webdriver.py”, line 42, in init
desired_capabilities=desired_capabilities)
File “/Library/Python/2.7/site-packages/selenium/webdriver/remote/webdriver.py”, line 98, in init
self.start_session(desired_capabilities, browser_profile)
File “/Library/Python/2.7/site-packages/selenium/webdriver/remote/webdriver.py”, line 188, in start_session
response = self.execute(Command.NEW_SESSION, parameters)
File “/Library/Python/2.7/site-packages/selenium/webdriver/remote/webdriver.py”, line 256, in execute
self.error_handler.check_response(response)
File “/Library/Python/2.7/site-packages/selenium/webdriver/remote/errorhandler.py”, line 165, in check_response
raise exception_class(value)
selenium.common.exceptions.WebDriverException: Message: The URL ‘http://http://127.0.0.1:4723/wd/hub/session’ did not map to a valid resource