Move json_dumps to src/util.py.

Author: riastradh-probcomp

src/metamodels/cgpm_metamodel.py

@@ -66,6 +66,7 @@
 from bayeslite.stats import arithmetic_mean
 from bayeslite.util import casefold
 from bayeslite.util import cursor_value
+from bayeslite.util import json_dumps
 
 import cgpm_schema.parse
 
@@ -783,8 +784,3 @@ def _default_numerical(bdb, generator_id, var):
     'cyclic': _default_numerical, # XXX can't do cyclic yet
     'numerical': _default_numerical,
 }
-
-# XXX Move these utilities elsewhere.
-
-def json_dumps(obj):
-    return json.dumps(obj, sort_keys=True)

src/util.py

@@ -103,3 +103,7 @@ def cursor_value(cursor, nullok=None):
     if len(row) != 1:
         raise ValueError('Non-unit cursor')
     return row[0]
+
+def json_dumps(obj):
+    """Return a JSON string of obj, compactly and deterministically."""
+    return json.dumps(obj, sort_keys=True)