# Your PR Title (What it does)
Fixes the pgvector python example notebook : one of the variables was
not referencing anything
## Before submitting
## Who can review?
Community members can review the PR once tests pass. Tag
maintainers/contributors who might be interested:
VectorStores / Retrievers / Memory
- @dev2049
- Added links to the vectorstore providers
- Added installation code (it is not clear that we have to go to the
`LangChan Ecosystem` page to get installation instructions.)
