class A():
 ...
  def Method(self):
    if self.a>b: Delete
  ...

al=[A() for x in xrange(10)]
...
for ax in a: ax.Method()

import random

class A(object):
    
    def __init__(self):
        self.a = random.choice(range(6)) 
        self.b = random.choice(range(6))
    
    @property
    def needs_remove(self):
        return self.a >= self.b
    
    def __unicode__(self):
        return "%s:%s:%s"%(self.a,self.b,self.needs_remove) 

if __name__=="__main__":
    lst = []
    for i in xrange(10):
        lst += A(),
    print "\n".join(map(lambda i:unicode(i),lst))
    print 20*"-" 
    for needs_remove in filter(lambda a:a.needs_remove,lst):
        lst.remove(needs_remove)
    print "\n".join(map(lambda i:unicode(i),lst))