Add missing country parameter to search API

[subhobhai943]

Summary

This PR resolves issue #12 by adding the missing country parameter to the search API. The parameter is available in the Perplexity API playground but was missing from the Python SDK.

Changes

🔧 Core Changes

• Added country parameter to SearchCreateParams - Added the parameter definition with proper typing (Optional[str])
• Updated both sync and async search methods - Added the country parameter to both SearchResource.create() and AsyncSearchResource.create() methods
• Added parameter documentation - Added docstring documentation explaining the parameter usage with examples

📚 Documentation & Examples

• Updated README.md - Added a new section documenting the country parameter with usage examples
• Created example script - Added examples/search_with_country.py demonstrating both sync and async usage

📝 Files Modified

• src/perplexity/types/search_create_params.py - Added country parameter definition
• src/perplexity/resources/search.py - Added country parameter to both sync and async methods
• README.md - Added documentation section for country parameter
• examples/search_with_country.py - New example demonstrating usage

Usage

from perplexity import Perplexity

client = Perplexity(api_key="your-api-key")

# Search with country restriction
search = client.search.create(
    query="latest tech news",
    country="US",  # ISO 3166-1 alpha-2 country code
    max_results=5
)

for result in search.results:
    print(f"{result.title}: {result.url}")

Parameter Details

• Type: Optional[str]
• Format: ISO 3166-1 alpha-2 country codes (e.g., "US", "GB", "CA", "DE", "FR", "JP", "AU", "IN")
• Purpose: Restricts search results to content from the specified country
• Availability: Both synchronous and asynchronous methods

Testing

The fix includes:

• ✅ Proper type hints for IDE autocomplete and type checking
• ✅ Documentation with parameter descriptions
• ✅ Example usage in both sync and async modes
• ✅ Comprehensive README documentation

Related Issues

• Fixes country parameter is missing #12 - country parameter is missing
• Addresses the discrepancy between the API playground and Python SDK

Backward Compatibility

This change is fully backward compatible as the country parameter is optional and defaults to omit. Existing code will continue to work without modification.

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Note: This parameter was already available in the Perplexity API but was missing from the Python SDK. This PR brings the SDK in line with the actual API capabilities shown in the playground.