Why doesn't input code return 'plants' as in 'Getting Started with Beautiful Soup' text (on page 30) ?

[Simon Evans]

Dear Peter Otten, 
I typed in (and did not copy and paste) the code as you suggested just now (6.28 pm, Sunday 12th July 2015), this is the result I got: 
----------------------------------------------------------------------------
Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>> from bs4 import BeautifulSoup
>>> with open("C:\Beautiful Soup\ecologicalpyramid.html","r")as f:
... soup = BeautifulSoup(f,"lxml")
  File "<stdin>", line 2
    soup = BeautifulSoup(f,"lxml")
       ^
IndentationError: expected an indented block
>>> soup = BeautifulSoup(f,"lxml")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'f' is not defined
>>>
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The first time I typed in the second line, I got the 
"Indentation error" 
the second time I typed in exactly the same code, I got the: 
"NameError:name 'f' is not defined"