Check if the polygons in the data are valid and closed.

is_valid_polygon.py

def is_valid_polygon(
    data: list    
) -> list:
    
    """"
    Check if the polygons in the data are valid and closed.

    Args:
        data: A list containing polygon data in the format:
            {'polygons': [{'coordinates': [{'latitude': float, 
                                            'longitude': float},
                                           {...},
                                           {...}],
                           'id': str},
                          {...},
                          {...}],
             'other_data': ...}

    Returns:
        The modified data with any closed polygons having their duplicate
        coordinate removed.
    """
    
    # Check if there any any polygons in the data.
    if len(data['polygons']) > 0:

       # Loop through each polygon.
        for polygon in data['polygons']:

            # Check if the polygon has at least 2 coordinates and the last 2
            # coordinates are the same (which means it's a closed polygon).
            if (len(polygon["coordinates"]) >= 2 and 
                polygon["coordinates"][-1]["latitude"] == 
                polygon["coordinates"][-2]["latitude"] and 
                polygon["coordinates"][-1]["longitude"] == 
                polygon["coordinates"][-2]["longitude"]):

                # If the polygon is closed, remove the last coordinate, which
                # is a duplicate of the first coordinate
                polygon["coordinates"].pop()
    
    # Return the data (with any modifications made to the polygons).
    return data