def difference_quotient(f, x, h):
    
    """Calculates the difference quotient of 'f' evaluated at x and x + h
    
    Parameters
    ----------
    f(x) : Callable function
    x : float
    h : float
    
    Returns
    -------
    '(f(x + h) - f(x)) / h'
    
    """
    
    return (f(x + h) - f(x)) / h