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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def import_cartopy():
 """ Try to import cartopy and print out a help message if it is not installed Returns --------- has_cartopy : bool cartopy : cartopy package if available else None """

    cartopy = None
    has_cartopy = True
    try:
        import cartopy
        WARNINGS['has_cartopy'] = True
    except ImportError:
        has_cartopy = False
        if not WARNINGS['cartopy']:
            print('-W- cartopy is not installed')
            print('    If you want to make maps, install using conda:')
            print('    conda install cartopy')
    WARNINGS['cartopy'] = True
    return has_cartopy, cartopy