Add license validation in init command

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Added
 
 - Added support for `packages`, `include` and `exclude` properties.
+- Added license validation in `init` command.
 
 ### Changed
 

poetry/console/commands/init.py

@@ -98,7 +98,7 @@ The <info>init</info> command creates a basic <comment>pyproject.toml</> file in
         question = self.create_question(
             "License [<comment>{}</comment>]: ".format(license), default=license
         )
-
+        question.validator = self._validate_license
         license = self.ask(question)
 
         question = self.create_question("Compatible Python versions [*]: ", default="*")
@@ -293,6 +293,13 @@ The <info>init</info> command creates a basic <comment>pyproject.toml</> file in
 
         return author
 
+    def _validate_license(self, license):
+        from poetry.spdx import license_by_id
+
+        license_by_id(license)
+
+        return license
+
     def _get_pool(self):
         from poetry.repositories import Pool
         from poetry.repositories.pypi_repository import PyPiRepository