You should write a simple function that takes string as input and checks if it is a valid Russian postal code, returning `true` or `false`.
A valid postcode should be 6 digits with no white spaces, letters or other symbols. Empty string should also return false. 
Please also keep in mind that a valid post code **cannot start with** `0, 5, 7, 8 or 9`
## Examples
Valid postcodes:
* 198328
* 310003
* 424000
Invalid postcodes:
* 056879
* 12A483
* 1@63
* 111
def zipvalidate(p):
    return len(p)==6 and p[0] in '12346' and all(d in '0123456789' for d in p)
def zipvalidate(p):
    return len(p)==6 and p[0] in '12346' and all(d in '0123456789' for d in p)