DHT11 error getting no readings

Hi am getting this error. I followed the codes given here

In nodered using grove node it works. But python code doesnt.

Thank you

temp = -1.00 C humidity =-1.00%
temp = -1.00 C humidity =-1.00%
^CTraceback (most recent call last):
File “temptest.py”, line 17, in
[temp,humidity] = grovepi.dht(sensor,blue)
File “/usr/local/lib/python3.5/dist-packages/grovepi.py”, line 301, in dht
number = read_i2c_block(address)
File “/usr/local/lib/python3.5/dist-packages/grovepi.py”, line 194, in read_i2c_block
return bus.read_i2c_block_data(address, 1)
File “/usr/local/lib/python3.5/dist-packages/smbus_cffi-0.5.1-py3.5-linux-armv7l.egg/smbus/util.py”, line 59, in validator
return fn(*args, **kwdefaults)
File “/usr/local/lib/python3.5/dist-packages/smbus_cffi-0.5.1-py3.5-linux-armv7l.egg/smbus/smbus.py”, line 257, in read_i2c_block_data
arg, data):
KeyboardInterrupt