def underscore_to_camelcase(value):
    """
    Converts underscore notation (something_named_this) to camelcase notation (somethingNamedThis)

    >>> underscore_to_camelcase('country_code')
    'countryCode'
    >>> underscore_to_camelcase('country')
    'country'
    >>> underscore_to_camelcase('price_GBP')
    'priceGBP'
    >>> underscore_to_camelcase('recommended_horizontal_resolution')
    'recommendedHorizontalResolution'
    >>> underscore_to_camelcase('postal_or_zip_code')
    'postalOrZipCode'
    >>> underscore_to_camelcase('test_ABC_test')
    'testABCTest'
    """
    words = value.split('_')
    return '%s%s' % (words[0], ''.join(x if x.isupper() else x.capitalize() for x in words[1:]))