diff --git a/src/gdiffer/cli.py b/src/gdiffer/cli.py
index c026cfa..c772c74 100644
--- a/src/gdiffer/cli.py
+++ b/src/gdiffer/cli.py
@@ -1,6 +1,3 @@
-"""CLI interface for git diff explainer."""
-
-import json
 import sys
 
 import click
@@ -14,8 +11,7 @@ from gdiffer.output import OutputFormat, OutputFormatter
 from gdiffer.parser import parse_diff
 
 
-def create_analysis(files: list[DiffFile], verbose: bool = False) -> DiffAnalysis:
-    """Create a complete analysis from parsed diff files."""
+def create_analysis(files, verbose=False):
     analysis = DiffAnalysis()
     language_detector = LanguageDetector()
     code_analyzer = CodeAnalyzer()
@@ -62,7 +58,6 @@ def create_analysis(files: list[DiffFile], verbose: bool = False) -> DiffAnalysi
             analysis.total_changes += hunk.new_lines
 
     analysis.total_files = len(files)
-
     return analysis
 
 
@@ -77,8 +72,7 @@ def create_analysis(files: list[DiffFile], verbose: bool = False) -> DiffAnalysi
     help="Output format",
 )
 @click.pass_context
-def main(ctx: click.Context, verbose: bool, output: str):
-    """A CLI tool that parses git diffs and provides intelligent explanations."""
+def main(ctx, verbose, output):
     ctx.ensure_object(dict)
     ctx.obj["verbose"] = verbose
     ctx.obj["output"] = output
@@ -89,8 +83,7 @@ def main(ctx: click.Context, verbose: bool, output: str):
 @click.option("--file", "-f", type=click.Path(exists=True), help="Read diff from file")
 @click.option("--stdin", "-s", is_flag=True, help="Read diff from stdin")
 @click.pass_context
-def explain(ctx: click.Context, diff_input: str | None, file: str | None, stdin: bool):
-    """Explain git diff changes with intelligent analysis."""
+def explain(ctx, diff_input, file, stdin):
     verbose = ctx.obj.get("verbose", False)
     output_format = ctx.obj.get("output", "terminal")
 
@@ -105,7 +98,7 @@ def explain(ctx: click.Context, diff_input: str | None, file: str | None, stdin:
         diff_content = diff_input
     else:
         click.echo("No diff provided. Use --stdin, --file, or pass diff as argument.", err=True)
-        click.echo("\nUsage examples:")
+        click.echo("\nUsage examples:", err=True)
         click.echo("  gdiffer explain 'diff --git a/file.py...'", err=True)
         click.echo("  git diff | gdiffer explain --stdin", err=True)
         click.echo("  gdiffer explain --file changes.diff", err=True)
@@ -140,8 +133,7 @@ def explain(ctx: click.Context, diff_input: str | None, file: str | None, stdin:
 @click.option("--file", "-f", type=click.Path(exists=True), help="Read diff from file")
 @click.option("--stdin", "-s", is_flag=True, help="Read diff from stdin")
 @click.pass_context
-def issues(ctx: click.Context, file: str | None, stdin: bool):
-    """Show only detected issues and security concerns."""
+def issues(ctx, file, stdin):
     diff_content = ""
 
     if stdin:
@@ -186,16 +178,17 @@ def issues(ctx: click.Context, file: str | None, stdin: bool):
             all_issues.sort(key=lambda x: severity_priority.get(x.get("severity", ""), 4))
 
             if ctx.obj.get("output") == "json":
-                click.echo(json.dumps(all_issues, indent=2))
+                click.echo(__import__("json").dumps(all_issues, indent=2))
             else:
                 for issue in all_issues:
                     severity = issue["severity"].upper()
-                    color = {
+                    color_map = {
                         "critical": "red",
                         "high": "orange3",
                         "medium": "yellow",
                         "low": "cyan",
-                    }.get(issue["severity"], "white")
+                    }
+                    color = color_map.get(issue["severity"], "white")
                     click.echo(f"[{color}][{severity}][/] {issue['title']}")
                     click.echo(f"  File: {issue['file']}:{issue['line']}")
                     click.echo(f"  {issue['description']}")
@@ -213,8 +206,7 @@ def issues(ctx: click.Context, file: str | None, stdin: bool):
 @click.option("--file", "-f", type=click.Path(exists=True), help="Read diff from file")
 @click.option("--stdin", "-s", is_flag=True, help="Read diff from stdin")
 @click.pass_context
-def summarize(ctx: click.Context, file: str | None, stdin: bool):
-    """Show only a brief summary of changes."""
+def summarize(ctx, file, stdin):
     diff_content = ""
 
     if stdin:
@@ -271,8 +263,7 @@ def summarize(ctx: click.Context, file: str | None, stdin: bool):
         sys.exit(1)
 
 
-def format_analysis_json(analysis: DiffAnalysis) -> str:
-    """Format analysis as JSON string."""
+def format_analysis_json(analysis):
     result = {
         "summary": {
             "total_files": analysis.total_files,
@@ -309,4 +300,4 @@ def format_analysis_json(analysis: DiffAnalysis) -> str:
 
         result["files"].append(file_data)
 
-    return json.dumps(result, indent=2)
+    return __import__("json").dumps(result, indent=2)