# Solution: Fixing duplicate methods and corrupted escape sequences in Python
**Category:** logic-errors
**Date:** 2026-01-18
**Project:** medical-graphrag-assistant
## Problem Symptom
The Python file `src/vectorization/vector_db_client.py` failed to import and showed multiple syntax errors.
Errors included:
- `Statements must be separated by newlines or semicolons`
- `Invalid character "\u5c" in token` (escaped backslash `\`)
- Duplicate method definitions for `insert_image_vector` and `search_similar_images`.
## Root Cause Analysis
During an automated edit process, the implementation logic was duplicated at the end of the file. However, the duplicated code was corrupted with escaped triple quotes (`\"\"\"` instead of `"""`) and other backslash escapes (`\`) that are invalid in raw Python string literals unless handled correctly. This led to a broken AST and unusable module.
## Investigation Steps
1. Attempted to run tests, which failed with import errors.
2. Used `read` to examine the file content.
3. Identified two identical blocks of code at the end of the file, one correctly formatted and one corrupted with escapes.
4. Used `python3 -c "import ast; ast.parse(...)"` to verify syntax.
## Working Solution
1. Remove the entire duplicated/corrupted block of code (lines 529-665 in this instance).
2. Ensure only one clean definition of each method exists with standard triple quotes (`"""`).
3. Verify syntax using the `ast` module before proceeding.
## Prevention Strategies
- **Pre-edit check**: Always read the target file range before applying string replacements.
- **Post-edit verification**: Run `python3 -m py_compile [file]` or an AST parse check immediately after every file modification.
- **LSP Integration**: Pay immediate attention to LSP "Expected expression" or "Unexpected indentation" errors after an edit.
## Cross-references
- `src/vectorization/vector_db_client.py`
- Sprint: `012-fix-test-failures`
