"Curly Braces" are used in Python to define a dictionary. A dictionary is a data structure that maps one value to another - kind of like how an English dictionary maps a word to its definition.
Python:
dict = {
"a" : "Apple",
"b" : "Banana",
}
They are also used to format strings, instead of the old C style using %, like:
ds = ['a', 'b', 'c', 'd']
x = ['has_{} 1'.format(d) for d in ds]
print x
['has_a 1', 'has_b 1', 'has_c 1', 'has_d 1']
They are not used to denote code blocks as they are in many "C-like" languages.
C:
if (condition) {
// do this
}