>>> import re
>>> regex = re.compile(r'^( )*([^ ])*( )*$')
>>> regex.search('   asdfgh   ').group(2)
'h'

p = re.compile("^(s+)((.+)(?=S).)(s+)$")
print p.search(" some textt of several words n").group(2)

p = re.compile("^(s+)((.+)(?=S).)(s+)$", re.DOTALL)
p.search(" somentext ").group(2) --> "somentext"

r1 = re.compile("^s+")
r2 = re.compile("s+$")
s = re.sub(p1, '', re.sub(p2, '', "tsomenttextn"))
s == "somenttext" # True

def strip(s):
     strip.r1 = re.compile("^s+")
     strip.r2 = re.compile("s+$")
     return re.sub(strip.r1, '', re.sub(strip.r2, '', s))

strip("tsomentext t") # -> "somentext"

def strip(s, symbols=r"s"):
     strip.r1 = re.compile("^[{}]+".format(symbols))
     strip.r2 = re.compile("[{}]+$".format(symbols))
     return re.sub(strip.r1, '', re.sub(strip.r2, '', s))

strip("tsomentext t") # -> "somentext"

regex = re.compile(r'^(s*)([^ ]*)(s*)$')

regex = re.compile(r'^( *)([^ ]*)( *)$')

import re
def reStrip( text, delim=" " ):
    return re.sub( '^['+re.escape(delim)+']*|['+re.escape(delim)+']*$', "", text )
reStrip( "   sdf   ", " s" ) // 'df'

>>> import re
>>> [re.fullmatch(r's*(.*?)s*', s, re.S).group(1) for s in ['', '  ', ' anbt']]
['', '', 'anb']

r'S+'

import re
result = re.search(r'S+', '    asdfgh   ggggggg    oooo')
print result.group(0)

asdfgh