code: def test_alpha_dim(self, df, kind, backend):
      plot = df.hvplot("x", "y", alpha="number", kind=kind)
      opts = Store.lookup_options(backend, plot, "style")
      assert opts.kwargs["alpha"] == "number"
      assert "number" in plot.vdims
      # Special matplotlib code to trigger an error that happens on render
      if backend == "matplotlib":
          mpl_renderer = hv.Store.renderers["matplotlib"]
          mpl_renderer.get_plot(plot)
  
imports: import hvplot
  import holoviews
  import numpy
  import pandas
  import pytest
  import xarray
  from holoviews import Store
  from holoviews.core.options import Options, OptionTree
label_desc: Use image node_id 6 for calling the TestOptions obj's underlying member method code with example usage: obj.test_alpha_dim(df, kind, backend) without return types