def find_maxima(x):
    """Find local maxima of x.

    Input arguments:
    x -- 1D list of real numbers


    Output:
    idx -- list of indices of the local maxima in x
    """
    maxima = []
    for index in range(len(x)-2):
        if x[index+1] > x[index] and x[index +1] > x[index+2]:
            maxima.append(index+1)
    
    return maxima


if __name__ == "__main__":
    x = [1, 2, 2, 1]
    print(find_maxima(x))