input: Write a python function to create a Person instance and call its greet method.
  assert create_and_greet("John", "Doe", 30) == "Hello, my name is John Doe and I am 30 years old."
  assert create_and_greet("Jane", "Smith", 25) == "Hello, my name is Jane Smith and I am 25 years old."
  assert create_and_greet("Alice", "Johnson", 40) == "Hello, my name is Alice Johnson and I am 40 years old."
output: class Person:
      def __init__(self, first_name, last_name, age):
          self.first_name = first_name
          self.last_name = last_name
          self.age = age
      
      def greet(self):
          return f"Hello, my name is {self.first_name} {self.last_name} and I am {self.age} years old."
  
  def create_and_greet(first_name, last_name, age):
      person = Person(first_name, last_name, age)
      return person.greet()