Fix docstring issue #234 (#235)

* Remove g

* Improve docstring

* Remove default format from signature

* Add example

* FIx

Author: aurorarossi

src/persistence/common.jl

@@ -107,11 +107,25 @@ function savegraph(fn::AbstractString, g::AbstractSimpleGraph; compress=nothing)
 end
 
 """
-    savegraph(file, g, d, format=LGFormat)
+    savegraph(file, d, format=LGFormat())
 
-Save a dictionary of `graphname => graph` to `file` in the format `format`.
+Save a dictionary `d` of `graphname => graph` to `file` in the format `format`.
 Return the number of graphs written.
 
+# Examples
+```jldoctest
+julia> g1 = SimpleGraph(5,8)
+{5, 8} undirected simple Int64 graph
+
+julia> g2 = SimpleGraph(7,10)
+{7, 10} undirected simple Int64 graph
+
+julia> d = Dict("graph_1" => g1, "graph_2" => g2);
+
+julia> savegraph("myfile.txt", d, LGFormat())
+2
+```
+
 ### Implementation Notes
 Will only work if the file format supports multiple graph types.
 """