Update app.py

app.py

@@ -1,5 +1,5 @@
 import streamlit as st
-from dynamical_system import invasion_fitness, invasion_fitness2, invasion_fitness3, pop_dynamics2
+from dynamical_system import invasion_fitness, invasion_fitness2, pop_dynamics2
 import numpy as np
 from tools import plot_3D_invfitness, plot_invasionfitness, make_interactive_video, plot_PIP
 from scipy.integrate import solve_ivp