def rand_number(length=0, exclude_numbers=()):
 _digits = digits[:]
 for excluded_number in set(exclude_numbers):
  _digits = _digits.replace(str(excluded_number), '')
 if (not _digits):
  raise ValueError('Failed return random number.')
 ru = ''.join((choice(_digits) for _ in xrange((length or randint(10, 30)))))
 return ru

def rand_number ( length = 0 , exclude_numbers = ( ) ) : _digits = digits [ : ] for excluded_number in set ( exclude_numbers ) : _digits = _digits . replace ( str ( excluded_number ) , '' ) if ( not _digits ) : raise ValueError ( 'Failed return random number.' ) ru = '' . join ( ( choice ( _digits ) for _ in xrange ( ( length or randint ( 10 , 30 ) ) ) ) ) return ru
create a random string only with numbers :return: a random string only composed by numbers .