Sudden IndentationError from copy-pasted code

Question

Set-up

I scrape housing ads per city, using Scrapy. Per city I create a spider, which I adjust (a little) per city when needed.

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Problem

I copy-pasted my code from City A in a .py file, intended to scrape City B. I've done this many times before. Now however I receive an IndentationError for the following lines in the code,

pl=[]
for key, value in df['postal'].iteritems():
    temp = value
    pl.append(str(temp))

The error is for temp and states IndentationError: expected an indented block. There is no indentation error if I run the code for city A. However, the copy-pasted code for B gives this error.

Moreover, if I enter or remove an extra white space, the lines run fine but then I receive an IndentationError at the next loop – enter/remove an extra white space at that loop will allow me to continue to the subsequent loop whereupon I receive the same error, etc.

I've also run python -m tabnanny yourfile.py as stated here, but to no effect: Clean bill of health.

What is going on here?

Answer 1

Left align all the copy pasted code and again give the proper indentation with tabs. copy pasted code sometimes takes wrong indentation.

Answer 2

Ok. This was a silly thing.

I copy pasted the entire file, but not correctly. That is, at the top of the file where I state which modules to input there was an unnecessary indent. I.e.

     import pandas as pd

instead of,

import pandas as pd

This resulted in the indentation error at any loop.

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