import re


def remove_outer_parens(s):
    """
    If there are outer parens when we don't need them, get rid of them
    Only one set
    
    >>> a = "(1910-1920)"
    >>> remove_outer_parens(a)
    '1910-1920'
    
    """
    ret_val = s
    m = re.match("\s*\((?P<inside_data>.*)\)\s*", s)
    if m:
        ret_val = m.group("inside_data")
    
    return ret_val