code: public double getStorageSize(String name, String defaultValue,
  	                             StorageUnit targetUnit) {
  		Preconditions.checkState(isNotBlank(name), "Key cannot be blank.");
  		String vString = get(name);
  		if (isBlank(vString)) {
  			vString = defaultValue;
  		}
  
  		// Please note: There is a bit of subtlety here. If the user specifies
  		// the default unit as "1GB", but the requested unit is MB, we will return
  		// the format in MB even thought the default string is specified in GB.
  
  		// Converts a string like "1GB" to to unit specified in targetUnit.
  
  		StorageSize measure = StorageSize.parse(vString);
  		return convertStorageUnit(measure.getValue(), measure.getUnit(),
  				targetUnit);
  	}
docs: Gets the Storage Size from the config, or returns the defaultValue. The
  unit of return value is specified in target unit.
  
  @param name - Key Name
  @param defaultValue - Default Value -- e.g. 100MB
  @param targetUnit - The units that we want result to be in.
  @return double -- formatted in target Units