Python list Go heavy

The title has faulty wordings, in fact it is this:

Suppose there are two lists: L1 = [1,2,3,4]; L2 = [1,2,5,6] then removes the L2 element contained in the L1

Direct this certainly is not possible:

def removeexists (L1, L2): For  E1 in L1:    if E1 in L2:      l1.remove (E1)

No matter what language can not do so, but a little different, it does not error and can go down, but the results are not expected.

As a result, since 1 in L1 has been removed, the iterator index points to the second element, but now the second element is 3, so the result of L1 is [2,3,4], and if L1 was originally [1,2,4,5], the result is [2,4], which is quite interesting ...

The solution does not matter, stick it a bit:

def removeexists (L1, L2):   = l1[:]  for in  l1t:    if in L2:      L1.remove (E1)

Python list Go heavy