# creating an empty hash
h = <[]> # => <[]>
h["a"]: 1 # => <["a" => 1]>
h["test"]: 2.4 # => <["a" => 1, "test" => 2.4]>
h[3]: "Hello" # => <["a" => 1, "test" => 2.4, 3 => "Hello"]>
# creating a hash with the constructor
h = Hash new # => <[]>