flake8 modifications

[Hema-Mathiyazhagan]

Issue: #41

Performed flake8 analysis on nzpy and fixed the errors

python3 ./nzpy_test.py 
Table customerAddress created successfully
1 rows inserted
1 rows inserted
1 rows inserted
Id = 1
Name = Jack
Address = High street, London
Email = jack4321@ibm.com
Table customerData created successfully
1 rows inserted
1 rows inserted
1 rows inserted
Id = 2
FirstName = Tom
LastName = Banks
Age = 28
Address = Park street, NY
Email = tom1234@ibm.com
Table row count is [3]
Create external table created successfully
External Table loaded successfully
After load from External Table, table row count is [6]

[Hema-Mathiyazhagan]

@sandippawar1412 could you please review this PR for the issue #41?