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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 read(alias_name, allow_none=False):
 """Get the raw docker link value. Get the raw environment variable for the docker link Args: alias_name: The environment variable name default: The default value if the link isn't available allow_none: If the return value can be `None` (i.e. optional) """

    warnings.warn('Will be removed in v1.0', DeprecationWarning, stacklevel=2)
    return core.read('{0}_PORT'.format(alias_name), default=None, allow_none=allow_none)