What you see here is the local Singaporean wildlife. Yes, you are right, it is a python, about 4-5m long (15ft), I saw it in a canal on my way to work, the canal is about 100m from my office. Apparently the python was shredding its old skin - if you look closer you will see remnants of old skin.
Now, it does not mean 20ft long pythons are roaming across Singapore daily. There is a coastal park nearby and that's where most likely the creature came from. I was thinking to call police but in 2 min it was gone back to the canal.
Moral of the story - walk more, you will see more interesting things.