java.lang.Throwable

java.lang.Throwable
 at com.intellij.openapi.diagnostic.Logger.error(Logger.java:48)
 at com.intellij.psi.impl.file.PsiPackageImpl.getChildren(PsiPackageImpl.java:245)
 at com.intellij.psi.impl.PsiElementBase.getLastChild(PsiElementBase.java:23)
 at com.jetbrains.python.psi.PyResolveUtil.getInnermostChildOf(PyResolveUtil.java:63)
 at com.jetbrains.python.psi.PyResolveUtil.treeCrawlUp(PyResolveUtil.java:110)
 at com.jetbrains.python.psi.PyResolveUtil.treeCrawlUp(PyResolveUtil.java:199)
 at com.jetbrains.python.psi.impl.ResolveImportUtil.suggestImportVariants(ResolveImportUtil.java:418)
 at com.jetbrains.python.psi.impl.PyReferenceExpressionImpl.getVariants(PyReferenceExpressionImpl.java:299)
 at com.intellij.codeInsight.completion.CompletionData.completeReference(CompletionData.java:284)
 at com.intellij.codeInsight.completion.CompletionVariant.addReferenceCompletions(CompletionVariant.java:179)
 at com.intellij.codeInsight.completion.CompletionData$1.run(CompletionData.java:93)
 at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:676)
 at com.intellij.codeInsight.completion.CompletionData.completeReference(CompletionData.java:88)
 at com.intellij.codeInsight.completion.LegacyCompletionContributor$2.consume(LegacyCompletionContributor.java:75)
 at com.intellij.codeInsight.completion.LegacyCompletionContributor$2.consume(LegacyCompletionContributor.java:2)
 at com.intellij.codeInsight.completion.LegacyCompletionContributor.processReference(LegacyCompletionContributor.java:106)
 at com.intellij.codeInsight.completion.LegacyCompletionContributor.processReferences(LegacyCompletionContributor.java:97)
 at com.intellij.codeInsight.completion.LegacyCompletionContributor.completeReference(LegacyCompletionContributor.java:72)
 at com.intellij.codeInsight.completion.LegacyCompletionContributor$1.addCompletions(LegacyCompletionContributor.java:56)
 at com.intellij.codeInsight.completion.CompletionProvider$1.run(CompletionProvider.java:33)
 at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:676)
 at com.intellij.codeInsight.completion.CompletionProvider.addCompletionVariants(CompletionProvider.java:31)
 at com.intellij.codeInsight.completion.CompletionContributor.fillCompletionVariants(CompletionContributor.java:142)
 at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:80)
 at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:71)
 at com.intellij.codeInsight.completion.JavaMethodMergingContributor.fillCompletionVariants(JavaMethodMergingContributor.java:35)
 at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:80)
 at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:71)
 at com.intellij.codeInsight.completion.CompletionService.performCompletion(CompletionService.java:133)
 at com.intellij.codeInsight.completion.CodeCompletionHandlerBase$3$1.run(CodeCompletionHandlerBase.java:156)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl$2.run(ProgressManagerImpl.java:130)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:154)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl.runProcess(ProgressManagerImpl.java:121)
 at com.intellij.codeInsight.completion.CodeCompletionHandlerBase$3.run(CodeCompletionHandlerBase.java:152)
 at com.intellij.openapi.application.impl.ApplicationImpl$5.run(ApplicationImpl.java:303)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:417)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:269)
 at java.util.concurrent.FutureTask.run(FutureTask.java:123)
 at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
 at java.lang.Thread.run(Thread.java:613)
 at com.intellij.openapi.application.impl.ApplicationImpl$1$1.run(ApplicationImpl.java:107)