In [33]:

    

def mean(numbers):
    if type(numbers) is list: #Checking if the input is a list or not. 
        len=0
        sum=0
        for x in numbers:
            sum=sum+x
            len=len+1
        return sum/len
    else:
        print("Please re-enter the input in the form of a list and run the function again.")


    

In [34]:

    

l=[1,2,3,4,5]


    

In [35]:

    

mean(l)


    

    
Out[35]:





3.0

In [36]:

    

l=[-11,2,-3,4,5]


    

In [37]:

    

mean(l)


    

    
Out[37]:





-0.6

In [38]:

    

l=1,2,3,4


    

In [39]:

    

mean(l)


    

    




Please re-enter the input in the form of a list and run the function again.

In [ ]: