Write if ready:, not if ready == True:

if already asks "is this true?". Comparing against True asks a narrower question, and it's rarely the one you meant.

Before

def has_stock(count):
    return count > 0

in_stock = has_stock(3)
if in_stock == True:
    print("ship it")

basket = ["tea", "scones"]
if len(basket) > 0 == True:
    print("basket has items")
else:
    print("basket looks empty?")

ship it
basket looks empty?

The second check reads like it should work, but comparisons chain: len(basket) > 0 == True means len(basket) > 0 and 0 == True, and 0 == True is false. The extra == True made a correct test wrong.

After

def has_stock(count):
    return count > 0

if has_stock(3):
    print("ship it")

basket = ["tea", "scones"]
if basket:
    print("basket has items")

ship it
basket has items

Why it works

Every value in Python has a truth value. Empty containers ([], {}, ""), 0, 0.0 and None are false; almost everything else is true. if basket: asks exactly "is there anything in it?".

== True asks something else: "does this equal the value True?". That only holds for True and 1:

for value in [True, 1, 2, "yes", ["tea"]]:
    print(repr(value), bool(value), value == True)

True True True
1 True True
2 True False
'yes' True False
['tea'] True False

Every one of those is true in an if, but only two pass == True.

When not to use it

When True must be told apart from other truthy values, say a setting that can be True, False or a number, write if setting is True: and make that choice visible. And a NumPy array or a pandas Series refuses a plain if because it has many values at once; use .any() or .all() to say which question you mean.