Why is code like

if a = "hello":pass

invalid in Python? The a = "Hello" is just a expression whose value is the Rvalue. It's valid in most languages like C or php. Some opinions?

While Python will allow you to chain assignment,

a = b = "hello"

it will not allow you to use it in an expression,

"hi" > b = "hello"    # => Syntax error

This is for safety, to keep you from accidentally using = when you meant ==