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* ``get_markers`` function to extract markers from adata and add ``pct.1``, ``pct.2`` fields
* ``write_mtx`` function to dump adata in cellranger mtx format
* ``clean_metadata`` function to merge and remove duplicates from ``adata.var`` after merging
Plotting:
* ``feature_plot`` function to plot hexbin feature plot on UMAP
* ``plot_composition`` function to plot composition of clusters based on other metadata
* ``expr_colormap`` function with custom colormap for expression