ruby hash send vs bracket code example

Example 1: ruby assign value to hash

grades = Hash.new
grades["Dorothy Doe"] = 9

Example 2: how ruby methods take in a hash of attributes

def create(name:, age:, gender:) #Main lesson on this line
	some_variable = SomeClass.new(name, age, gender)
    some_variable.save #save is an instance method undefined here
    some_variable
end