Setter function for the cell_ID slot. Directly replaces (sets) this slot
Details
Data for each spatial unit is expected to agree on a single set of cell_IDs
that are shared across any feature types. These cell_IDs are stored within
the giotto object's cell_ID slot. 
Pass NULL to cell_IDs param in order to delete the entry. 
Pass 'initialize' to cell_IDs param in order to initialize the
specified entry. 
NOTE: The main purpose of the setter is to initialize, as cell_ID
values are AUTOMATICALLY updated every time initialize() is called
on the giotto object.
See also
get_cell_id
Other functions to set data in giotto object:
get_cell_id(),
get_feat_id(),
setCellMetadata(),
setDimReduction(),
setExpression(),
setFeatureInfo(),
setFeatureMetadata(),
setGiottoImage(),
setMultiomics(),
setNearestNetwork(),
setPolygonInfo(),
setSpatialEnrichment(),
setSpatialGrid(),
setSpatialLocations(),
setSpatialNetwork(),
set_NearestNetwork(),
set_cell_metadata(),
set_dimReduction(),
set_expression_values(),
set_feat_id(),
set_feature_info(),
set_feature_metadata(),
set_giottoImage(),
set_multiomics(),
set_polygon_info(),
set_spatialGrid(),
set_spatialNetwork(),
set_spatial_enrichment(),
set_spatial_locations()
