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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 get_internal_modules(key='exa'):
 """ Get a list of modules belonging to the given package. Args: key (str):
 Package or library name (e.g. "exa") """

    key += '.'
    return [v for k, v in sys.modules.items() if k.startswith(key)]