def zshift(s):
 s = s.lstrip()
 i = 0
 while s.startswith((ZERO, '0')):
  s = re.sub(('^(0|%s)\\s*' % ZERO), '', s, 1)
  i = (i + 1)
 return (s, i)

def zshift ( s ) : s = s . lstrip ( ) i = 0 while s . startswith ( ( ZERO , '0' ) ) : s = re . sub ( ( '^(0|%s)\\s*' % ZERO ) , '' , s , 1 ) i = ( i + 1 ) return ( s , i )
returns a -tuple .