Drawing line of regression onto scatter graph in python

I am trying to draw the line of regression onto a scatter graph. I have two functions:

def place_y(x, slope, intercept):
    return slope * x + intercept


def draw_line_of_regression():
    """The line of regression can be used to predict further values"""
    import matplotlib.pyplot as plt  # used to draw graph
    from scipy import stats

    # Example shows relationship between age and speed
    age_x = [5, 7, 8, 7, 2, 17, 2, 9, 4, 11, 12, 9, 6]
    speed_y = [99, 86, 87, 88, 111, 86, 103, 87, 94, 78, 77, 85, 86]

    slope, intercept, r, p, std_error = stats.linregress(age_x, speed_y)
    # gets variables used in drawing the line of regression

    line_of_regression = list(map(place_y(age_x, slope, intercept), age_x))

    plt.scatter(age_x, speed_y)  # draws scatter graph
    plt.plot(age_x, line_of_regression)
    plt.show()  # shows the graph


draw_line_of_regression()

When this is run there is an error with the place_y() function. Error:

    return slope * x + intercept
TypeError: can't multiply sequence by non-int of type 'numpy.float64

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