is_in

@register.filter
def is_in(value, arg):
    '''It performs the same action as Python in statement.
       It returns True if value is in arg, False if not or any error occur.
    
       For example:
       {{ 'abc'|is_in:'www.abc.com'}}   -> 'abc' in 'www.abc.com'
       
       x = 5
       l = [3,4,5,6]
       {{ x|is_in:l}                    -> x in l
    '''
    
    try:
        return value in arg
    except:
        return False