gistfile1.py

def find_multiples(factor, end):                                                                                                                                                      
    """Creates a list of multiples less than a given end                                                                                                                              
       value from the given factors.                                                                                                                                                  
    """                                                                                                                                                                               
    return range(factor, end, factor)                                                                                                                                                 
                                                                                                                                                                                      
                                                                                                                                                                                      
def collect_and_apply(factors, end=1000, func=None):                                                                                                                                  
    """Merges lists of multiples of the given factors                                                                                                                                 
       less than the end value (1000 by default). If                                                                                                                                  
       a function is passed as an optional argument,                                                                                                                                  
       it will be applied to the result prior to return.                                                                                                                              
    """                                                                                                                                                                               
    result = set()                                                                                                                                                                    
                                                                                                                                                                                      
    try:                                                                                                                                                                              
        for factor in factors:                                                                                                                                                        
            result.update(set(find_multiples(factor, end)))                                                                                                                           
                                                                                                                                                                                      
        # Test to see if a function was passed, if it was, apply                                                                                                                      
        # it to the result, otherwise simply return the result.                                                                                                                       
        if func is None:                                                                                                                                                              
            return result                                                                                                                                                             
        else:                                                                                                                                                                         
            return func(result)                                                                                                                                                       
                                                                                                                                                                                      
    except TypeError:                                                                                                                                                                 
        print "Factors argument must be iterable."                                                                                                                                    
                                                                                                                                                                                      
                                                                                                                                                                                      
if __name__ == '__main__':                                                                                                                                                            
    # Notice that we can supply the third argument, even if we leave                                                                                                                  
    # out the second (end)? This is because we explicitly state that                                                                                                                  
    # our second argument is the 'func' argument. As such, the default                                                                                                                
    # 1000 will be used for 'end'                                                                                                                                                     
    print collect_and_apply((3, 5), func=sum)