Calpurnia, the housekeeper of the Finch family in Harper Lee's novel, To Kill a Mockingbird, is more than just a maid and cook to Atticus, Jem and Scout. She is like a member of the family and almost a surrogate mother to the two kids. She has taught Scout to write, and she disciplines them when necessary. She shows them the same love that she would show her own children and, like most of the town, she realizes that Atticus treats her with more respect than she would find elsewhere in the white community.
Aunt Alexandra, however, believes Jem and Scout need more motherly guidance, and when she comes to live temporarily, she tries to convince Atticus to get rid of Calpurnia. (Scout misunderstands this when she overhears their conversation and thinks initially that Alexandra is trying to rid the home of her!) "We don't need her now," Alexandra tells Atticus. But Atticus is firm.
"She's a faithful member of this family, and you'll simply have to accept things the way they are."
This is typical of Alexandra for several reasons. She believes she knows best when it comes to parenting matters, and she is also far less tolerant of black people than her brother. Since she basically wears the pants in her own family--she domineers her husband--she expects to control the Finch household in Maycomb as well.
The fight that follows between the two kids makes Scout happy for several reasons. The fight with her older, bigger brother is a draw after Atticus breaks it up; Jem is sent to bed at the same time as Scout (he normally is allowed to stay up later); and he says, "Night, Scout," afterward, a sign that their recent feuding may be at an end. Also, the fight has united the three Finches against Alexandra.