You can use the following code, it worked for me perfectly.
import boto3
ec2 = boto3.resource('ec2')
instance = ec2.create_instances(
ImageId = 'ami-009d6802948d06e52',
MinCount = 1,
MaxCount = 1,
InstanceType = 't2.micro',
KeyName = 'nabarupa',
SubnetId = 'subnet-0yhg678990d56c277')
print (instance[0].id)
Hope this helps.