I agree, but it seems like something more should be added.  help(Sum) is rather 
un-informative at first glance.  On second glance, you can find all the basics 
barried in various parts of the class documentation, but shouldn't there be a 
clean 1-off example to begin with?  If you point me to a good style-example, I 
can fill in the blank.  In the mean-time, I'll push a cleaned version.



On Wed, 13 Feb 2013, Aaron Meurer wrote:

>> @@ -21,7 +21,12 @@ def _free_symbols(function, limits):
>>
>>
>>  class Sum(Expr):
>> -    """Represents unevaluated summation."""
>> +    """Represents unevaluated summation.
>> +    For example, Sum(i,(i,2,10))
>> +    represents the summation of the sequence 2,3,4,...,9,10
>> +
>> +    deep
>
> This probably shouldn't be here.
>
> ---
> Reply to this email directly or view it on GitHub:
> https://github.com/sympy/sympy/pull/1781/files#r3001981
>