Testing validity of for...in...

[Richard Philips]

Hi,

 From the "The Pragmatic Programmer / Dave Thomas, Andy Hunt",
I acquired the habit to insert assertions in function declarations:

def maxlength(mylist):
    assert isinstance(mylist, list), "A list with strings"
    max = -1
    for item in list:
        if len(item)>max:
           max = len(item)
    return max


But if you look at the code, maxlength is meaningful if mylist supports 
the "for ... in ...".

Is there an easy way to test if "mylist" supports  "for ... in ..." ?

Thank you,

Richard

-- 
================================================================
Dr. Richard PHILIPS
University of Antwerp
Systemmanager Anet

Phone: +32 3 820.21.53
Fax:   +32 3 820.21.59
GSM:   0478/36.76.28
Email: Richard.Philips at ua.ac.be
================================================================