problem with newlines in regexp substitution

See the following results:

Python 2.3.5 (#62, Feb 8 2005, 16:23:02) [MSC v.1200 32 bit (Intel)] on win32
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import re
s = "1"
re.sub('1','\\n',s)
'\n'
'\\n'
'\\n'
re.sub('1',r'\\n',s)
'\\n'
s.replace('1','\\n')
'\\n'
repl = '\\n'
re.sub('1',repl,s)
'\n'
s.replace('1',repl)
'\\n'

Why is the behaviour of the regexp substitution so weird and can I prevent that? It breaks my asumptions and thus my code.

Regards,
Florian Schulze

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