You can safely ignore it. @pyimport creates an module __anon__ (which is assigned to plt in this case) that has definitions for the Python functions in the Python module. The warning is telling you that this module creates its own "transpose" function instead of extending Base.transpose. (It is a warning because in many cases a module author would have intended to add a new method to Base.transpose instead.)
This is fine. transpose in other modules still refers to Base.transpose, and plt.transpose refers to the pylab one (== numpy transpose). --SGJ PS. By the way, I would normally import just pyplot and not pylab. The pylab module is useful in Python because it imports numpy too, and without that you wouldn't have a lot of basic array functionality. But in Julia you already have the equivalent of numpy built in to Julia Base. Also, I would tend to recommend the Julia PyPlot module over manually importing pyplot. The PyPlot module adds some niceties like IJulia inline plots and interactive GUI plots, whereas pylab is imported by default in non-interactive mode.
