Harry was turning over the wizard coins and looking at them. He had just thought of something that made him feel as though the happy balloon inside him had got a puncture. "Um –– Hagrid?"
"Mm?" said Hagrid, who was pulling on his huge boots. "I haven't got any money –– and you heard Uncle Vernon last night ... he won't pay for me to go and learn magic."
"Don't worry about that," said Hagrid, standing up and scratching his head. "D'yeh think yer parents didn't leave yeh anything?"
"But if their house was destroyed ––"
"They didn' keep their gold in the house, boy! Nah, first stop fer us is Gringotts. Wizards' bank. Have a sausage, they're not bad cold –– an' I wouldn' say no teh a bit o' yer birthday cake, neither."
(Harry Potter and the Sorcerer's Stone)
What does ‘nah’ mean? (If it meant ‘no’, its location would be better in the previous sentence, I think. And so I suspect it might have some other meaning, but to find nothing except ‘no’.)