How do I get rid of repeating special characters with regular expressions?

I want to get rid of all the repetitive dots except the ones that were one dot.

Sources:

(1) "a... b."
(2) "a....... b... c."

Results I want:

(1) "a b."
(2) "a b c."

Code:

import re

a = "a... b."
b = "a....... b... c."

result = re.sub("[^a-zA-Z0-9 \\.{1}]", "", a)
print(result)

result = re.sub("[^a-zA-Z0-9 \\.{1}]", "", b)
print(result)

result = re.sub("[^a-zA-Z0-9 ][\\.{2,}]", "", a)
print(result)

result = re.sub("[^a-zA-Z0-9 ][\\.{2,}]", "", b)
print(result)

Doesn’t work.

How can I do to get my results?

>Solution :

Below code can do the needed task

import re
result = re.sub("\\.{2,}","","a....b....c.d....e.")
print(result)

Result will be-
abc.de.