Correct mdbook

Author: frankmcsherry

mdbook/src/chapter_2/chapter_2_4.md

@@ -12,7 +12,6 @@ As an example, if we were to inspect
 # use timely::dataflow::Scope;
 # use differential_dataflow::VecCollection;
 # use differential_dataflow::lattice::Lattice;
-# use differential_dataflow::operators::Reduce;
 # fn example<G: Scope>(manages: &VecCollection<G, (u64, u64)>)
 # where G::Timestamp: Lattice
 # {

mdbook/src/chapter_2/chapter_2_6.md

@@ -10,7 +10,6 @@ For example, to produce for each manager their managee with the lowest identifie
 # use timely::dataflow::Scope;
 # use differential_dataflow::VecCollection;
 # use differential_dataflow::lattice::Lattice;
-# use differential_dataflow::operators::Reduce;
 # fn example<G: Scope>(manages: &VecCollection<G, (u64, u64), i64>)
 # where G::Timestamp: Lattice
 # {

mdbook/src/chapter_2/chapter_2_7.md

@@ -9,7 +9,7 @@ As an example, we can take our `manages` relation and determine for all employee
 # extern crate differential_dataflow;
 # use timely::dataflow::Scope;
 # use differential_dataflow::VecCollection;
-# use differential_dataflow::operators::{Join, Iterate, Threshold};
+# use differential_dataflow::operators::{Join, Iterate};
 # use differential_dataflow::lattice::Lattice;
 # fn example<G: Scope>(manages: &VecCollection<G, (u64, u64)>)
 # where G::Timestamp: Lattice
@@ -45,7 +45,7 @@ In the example above, we could rewrite
 # extern crate differential_dataflow;
 # use timely::dataflow::Scope;
 # use differential_dataflow::VecCollection;
-# use differential_dataflow::operators::{Join, Threshold};
+# use differential_dataflow::operators::Join;
 # use differential_dataflow::operators::{Iterate, iterate::VecVariable};
 # use differential_dataflow::lattice::Lattice;
 # fn example<G: Scope>(manages: &VecCollection<G, (u64, u64)>)

mdbook/src/chapter_5/chapter_5_4.md

@@ -23,7 +23,6 @@ extern crate timely;
 extern crate differential_dataflow;
 
 use differential_dataflow::operators::Join;
-use differential_dataflow::operators::Threshold;
 use differential_dataflow::operators::Iterate;
 use differential_dataflow::operators::arrange::ArrangeByKey;