Create or append a mongo aggregation stage

Create or append a mongo aggregation stage

add_stage(x, ...)

# S3 method for default
add_stage(x, ...)

# S3 method for mongopipe
add_stage(x, type, ...)

Arguments

x	Object of class mongo or mongo_pipe
...	query
type	Name of the stage.

Value

Object of type mongopipe.