Python Scipy scipy.optimize.curve_fit() function is used to find the best-fit parameters using a least-squares fit. The curve_fit method fits our model to the data. The curve fit is essential to find the optimal set of parameters for the defined function that best fits the provided set of observations. Syntax of scipy.optimize.curve_fit(): scipy.optimize.curve_fit(f, xdata, ydata, sigma=None, p0=None) Parameters f It is the model function. Takes independent variable as first argument and the parameters to fit as separate remaining arguments.