import math


def largest_numeric_increase_infant_mortality(data_by_country):
    """ Which country had the largest increase in Infant mortality for both sexes from 2005 to 2015?

    Parameters:
        data_by_country: dictionary with different data for countries.
    
    Returns:
        Tuple(String, String) - (Question, country name).
    """
    data_series = 'Infant mortality for both sexes (per 1,000 live births)'
    start_year = 2005
    end_year = 2015

    largest = -math.inf
    result = ''

    for ID in data_by_country:
        if data_series in data_by_country[ID]:
            # finds all data between 2005 and 2015
            everything_between = []

            for data in data_by_country[ID][data_series]:
                if data['year'] >= start_year and data['year'] <= end_year:
                    everything_between.append(data)
            
            # finds the difference between the infant mortality from the max and min year
            if len(everything_between) > 1:
                max_year = max(everything_between, key=lambda d: d['year'])
                min_year = min(everything_between, key=lambda d: d['year'])
                diff = max_year['value'] - min_year['value']

                if diff > largest:
                    largest = diff
                    result = data_by_country[ID]['name']

    return ('Which country had the largest increase in Infant mortality for both sexes from 2005 to 2015?', result)