Grove Base Kit - dht not installed

I get:
pi@raspberrypi:~/grove.py $ pip3 install seeed_dht
Collecting seeed_dht
Could not find a version that satisfies the requirement seeed_dht (from versions: )
No matching distribution found for seeed_dht

if I try and re-install dht
This is my original problem:
pi@raspberrypi:~/grove.py $ sudo ./lesson_7.py
Traceback (most recent call last):
File “./lesson_7.py”, line 5, in
from seeed_dht import DHT
ImportError: No module named ‘seeed_dht’

The source code from seeed:

#!/usr/bin/env python3
import time
from seeed_dht import DHT
from grove.display.jhd1802 import JHD1802
def main():
# Grove - 16x2 LCD(White on Blue) connected to I2C port
lcd = JHD1802()
# Grove - Temperature&Humidity Sensor connected to port D5
sensor = DHT(‘11’, 5)
while True:
humi, temp = sensor.read()
print(‘temperature {}C, humidity {}%’.format(temp, humi))
lcd.setCursor(0, 0)
lcd.write(‘temperature: {0:2}C’.format(temp))
lcd.setCursor(1, 0)
lcd.write(‘humidity: {0:5}%’.format(humi))
time.sleep(1)
if name == ‘main’:
main()

I have used the instructions at the link below and it works fine but now I have a muddle of python modules to untangle!