def getDivisors(n):
    """
        input: positive integer 'n' >= 1
        returns all divisors of n (inclusive 1 and 'n')
    """
    
    # precondition
    assert isinstance(n,int) and (n >= 1), "'n' must been int and >= 1"

        
    ans = [] # will be returned.
    
    for divisor in range(1,n+1):
        
        if n % divisor == 0:
            ans.append(divisor)
       
       
    #precondition
    assert ans[0] == 1 and ans[len(ans)-1] == n, \
    "Error in function getDivisiors(...)"
    
    
    return ans