First time making a python project implementing bellman-ford, and I am getting stuck

import math edges = [ ("GBP", "USD", 1.35) ("GBP", "EUR", 1.15) ("USD", "GBP", 0.74) ("USD", "EUR", 0.85) ("EUR", "GBP", 0.87) ("EUR", "USD", 1.18) ("THB", "USD", 0.030) ("THB", "EUR", 0.025) ("THB", "GBP", 0.027) ] arbitrage = [] transformed_edges = [] for v,w, rate in edges: #v being the start node, w being the end node weight = -math.log(rate) transformed_edges.append(v, w , weight) def arbitrage_exists(vertices, edges, source): distance = {v: float('inf') for v in vertices} distance[source] = 0 for i in range(len(vertices) - 1): for u, v, weight in transformed_edges: if distance[u] + w < distance[v]: distance[v] = distance[u] + w for u, v, weight in transformed_edges: if distance[u] + w < distance[v]: arbitrage = (u, v, weight) return True return False

This is what I have so far it is my first time working on such a project in python (and haven't been using python for a long time still very unexperienced) so any advice is appreciated.