trouble with mandelbrot example

mojo: /lib64/libtinfo.so.6: no version information available (required by mojo)
/home/nbecker/mojo/mandel.mojo:59:1: error: TODO: expressions are not yet supported at the file scope level
show_plot(compute_mandelbrot())
^
/home/nbecker/mojo/mandel.mojo:36:23: error: use of unknown declaration 'Tensor'
def show_plot(tensor: Tensor[float_type]):
                      ^~~~~~
/home/nbecker/mojo/mandel.mojo:11:26: error: use of unknown declaration 'ComplexFloat64'
def mandelbrot_kernel(c: ComplexFloat64) -> Int:
... more errors
mojo: error: failed to parse the provided Mojo