import re

FILTER_RE = re.compile('[-[\]{}()*+?.,\\^$|#\s]')
REPLACE_WITH = ''
def filter_helper(object_list, attr, term):
    """
    Helper method for filtering object_lists.
    
    @param  object_list     An array of objects to filter.
    @param  attr            An attribute on the object to filter the list by.
    @param  term            The filter term to look for in the attribute.
    @return The filtered list
    """
                
    # remove special characters from the filter term
    escaped_term = FILTER_RE.sub(REPLACE_WITH, term)
    
    
    def compare(x):
        """
        Function that compares the value to the filter term.

        @param  x    The object we are looking at.
        @return True if we have a match otherwise False.
        """
        
        # get the attribute off the object
        v = getattr(x, attr)
        
        # attribute is a method so get the return value
        if callable(v): v = v()
        
        # remove special characters from the attribute value
        ev = FILTER_RE.sub(REPLACE_WITH, v)
        
        # if the term is an exact match or the escaped term is in the escaped attr
        if term == v or re.search(escaped_term, ev, re.I):
            return True
        return False
    
    # run the compare function through the list to create the filtered list
    return filter(compare, object_list)