Dynamically instantiate MPContribs client (#870)

* Dynamically instantiate MPContribs client

* Linting

* Fix MPRester test

Author: Jason Munro

mp_api/client/mprester.py

@@ -186,6 +186,7 @@ def __init__(
         self.use_document_model = use_document_model
         self.monty_decode = monty_decode
         self.mute_progress_bars = mute_progress_bars
+        self._contribs = None
 
         self._deprecated_attributes = [
             "eos",
@@ -221,21 +222,6 @@ def __init__(
         # Check if emmet version of server is compatible
         emmet_version = MPRester.get_emmet_version(self.endpoint)
 
-        try:
-            from mpcontribs.client import Client
-
-            self.contribs = Client(api_key, headers=self.headers, session=self.session)
-        except ImportError:
-            self.contribs = None
-            warnings.warn(
-                "mpcontribs-client not installed. "
-                "Install the package to query MPContribs data, or construct pourbaix diagrams: "
-                "'pip install mpcontribs-client'"
-            )
-        except Exception as error:
-            self.contribs = None
-            warnings.warn(f"Problem loading MPContribs client: {error}")
-
         if version.parse(emmet_version.base_version) < version.parse(
             _MAPI_SETTINGS.MIN_EMMET_VERSION
         ):
@@ -363,6 +349,29 @@ def __molecules_getattr__(_self, attr):
                 rester,
             )
 
+    @property
+    def contribs(self):
+        if self._contribs is None:
+            try:
+                from mpcontribs.client import Client
+
+                self._contribs = Client(
+                    self.api_key, headers=self.headers, session=self.session
+                )
+
+            except ImportError:
+                self._contribs = None
+                warnings.warn(
+                    "mpcontribs-client not installed. "
+                    "Install the package to query MPContribs data, or construct pourbaix diagrams: "
+                    "'pip install mpcontribs-client'"
+                )
+            except Exception as error:
+                self._contribs = None
+                warnings.warn(f"Problem loading MPContribs client: {error}")
+
+        return self._contribs
+
     def __enter__(self):
         """Support for "with" context."""
         return self

mp_api/client/routes/materials/elasticity.py

@@ -2,11 +2,11 @@
 
 import warnings
 from collections import defaultdict
-from mp_api.client.core.utils import validate_ids
 
 from emmet.core.elasticity import ElasticityDoc
 
 from mp_api.client.core import BaseRester
+from mp_api.client.core.utils import validate_ids
 
 
 class ElasticityRester(BaseRester[ElasticityDoc]):

tests/test_mprester.py

@@ -118,7 +118,7 @@ def test_get_entries(self, mpr):
         syms = ["Li", "Fe", "O"]
         chemsys = "Li-Fe-O"
         entries = mpr.get_entries(chemsys)
-        sorted_entries = mpr.get_entries(chemsys, sort_by_e_above_hull=True)
+        sorted_entries = mpr.get_entries(chemsys)
 
         elements = {Element(sym) for sym in syms}
         for e in entries: