Add a radio wigdet for cost function

app.py

@@ -9,8 +9,12 @@ st.markdown('*\"Parametrised models are simply functions that depend on inputs a
 
 st.latex(r'''h(\boldsymbol x, \boldsymbol w)= \sum_{k=1}^{K}\boldsymbol w_{k} \phi_{k}(\boldsymbol x)''')
 
+
+# Sidebar inputs
 number_of_observations = st.sidebar.slider('Number of observations', min_value=50, max_value=150, value=50)
 noise_standard_deviation = st.sidebar.slider('Standard deviation of the noise', min_value = 0.0, max_value=2.0, value=0.25)
+cost_function = st.sidebast.slider('What cost function you want to use for the fitting?',
+                                  ('RMSE-Loss', 'Huber-Loss'))
 
 np.random.seed(2)