{% if ast %}
## Abstract Syntax Tree (AST) for context
```ast
{{ast}}
```
{% endif %}

## Output Format
Provide a YAML object matching the $Mutants schema:
```python
class SingleMutant(BaseModel):
    function_name: str = Field(..., description="The name of the function where the mutation was applied.")
    type: str = Field(..., description="The type of the mutation operator used.")
    description: str = Field(..., description="A brief description detailing the mutation applied.")
    line_number: int = Field(..., description="Line number where the mutation was applied.")
    original_code: str = Field(..., description="The original line of code before mutation. Ensure proper formatting for YAML literal block scalar.
    mutated_code: Ones Field(..., description="The mutated line of code. Please annotate with a {{language}} syntax comment explaining the mutation. Ensure proper formatting for YAML literal block scalar.")

class Mutants(BaseModel):
    source_file: str = Field(..., description="The name of the source file where mutations were applied.")
    mutants: List[SingleMutant] = Field(..., description="A list of SingleMutant instances each representing a specific mutation change.")
```

## Source Code to Mutate: {{src_code_file}}
```{{language}}
{{numbered_src_code}}
```

## Task
1. Analyze the source code line by line.
2. Focus on function blocks and critical areas.
3. Ensure mutations provide insights into code quality.
4. Organize output by ascending line numbers.
5. Do not include manually added line numbers in your response.
6. Generate single-line mutations only.

## Example Output
```yaml
source_file: {{src_code_file}}
mutants:
  - function_name: <function name>
    type: <mutation type>
    description: <brief mutation description>
    line_number: <line number>
    original_code: |
      <original code>
    mutated_code: |
      <mutated code and {{language}} comment explaining mutation>
``` 
Produce mutants that challenge the robustness of the code without breaking core functionality. Provide only the YAML output. Do not include any additional explanations or comments.