Merge pull request #432 from bjodah/define-lambdify-even-without-numpy

Add a lambdify func. that throws ModuleNotFoundError when numpy missing

Author: isuruf

symengine/__init__.py

@@ -55,7 +55,11 @@
 
     def lambdify(args, exprs, **kwargs):
         return Lambdify(args, *exprs, **kwargs)
-
+else:
+    def __getattr__(name):
+        if name == 'lambdify':
+            raise AttributeError("Cannot import numpy, which is required for `lambdify` to work")
+        raise AttributeError(f"module 'symengine' has no attribute '{name}'")
 
 __version__ = "0.9.2"