Python Code Reviewer
awk, 64 56 54 bytes
/^$/{i=0}/./{if(!i++)print&quot;# This is not pythonic!&quot;}1

Test:
echo '/^$/{i=0}/./{if(!i++)print&quot;# This is not pythonic!&quot;}1' &gt; solution.awk
awk -f solution.awk &lt; pyth.py
awk -f solution.awk &lt; pyth.py

Explanation:
/^$/ - matches empty line,
/./ - matches non-empty line,
1 - matches each line. No body is equivalent to {print;} - each line of input is printed.