Thai Chicken Coconut Soup

Preparation : Heat the coconut milk in a pot. Add everything else. As the lemon grass is inedible, put it in a tea ball and immerse the ball in the soup so you can retrieve it later. Cook until the chicken is done and the soup is hot (30 minutes?). Taste to see if it needs more limes (it always does) or more hot peppers (it's better to start mild and build up to the desired level of spicyness