Question: Who is the screenwriter of the documentary about and named after the country containing Chumbai Valley?

full_context: Document 1: Mrinal Sen: After making five more films, he made a film with a shoestring budget provided by the Government of India. This film, Bhuvan Shome (Mr. Shome, 1969), finally launched him as a major filmmaker, both nationally and internationally. Bhuvan Shome also initiated the "New Cinema" film movement in India.
Document 2: Sikkim: Phuntsog Namgyal was succeeded in 1670 by his son, Tensung Namgyal, who moved the capital from Yuksom to Rabdentse (near modern Pelling). In 1700, Sikkim was invaded by the Bhutanese with the help of the half-sister of the Chogyal, who had been denied the throne. The Bhutanese were driven away by the Tibetans, who restored the throne to the Chogyal ten years later. Between 1717 and 1733, the kingdom faced many raids by the Nepalese in the west and Bhutanese in the east, culminating with the destruction of the capital Rabdentse by the Nepalese. In 1791, China sent troops to support Sikkim and defend Tibet against the Gorkha Kingdom. Following the subsequent defeat of Gorkha, the Chinese Qing dynasty established control over Sikkim.
Document 3: Sukumar Ray (film): Sukumar Ray is a 1987 Bengali short documentary film made by Satyajit Ray on his father, Sukumar Ray. It was released during the birth centenary year of Sukumar Ray, who was born on 30 October 1887. The thirty minutes documentary features the life and some of the works by Sukumar Ray in the form of paintings, photographs and readings. This is the last documentary made by Satyajit Ray as a tribute to his father, before he died in 1992. The documentary used Sukumar Ray's photographs and paintings than video recording as the film was considerably a new medium in India when Sukumar Ray died in 1923.
Document 4: Gangtok: Gangtok rose to prominence as a popular Buddhist pilgrimage site after the construction of the Enchey Monastery in 1840. In 1894, the ruling Sikkimese Chogyal, Thutob Namgyal, transferred the capital to Gangtok. In the early 20th century, Gangtok became a major stopover on the trade route between Lhasa in Tibet and cities such as Kolkata (then Calcutta) in British India. After India won its independence from Britain in 1947, Sikkim chose to remain an independent monarchy, with Gangtok as its capital. In 1975, after the integration with the union of India, Gangtok was made India's 22nd state capital.
Document 5: Chonala masoni: The species is named the Chumbi wall after the Chumbi Valley where it was "presumed" to have been collected by a native collector and passed on to Henry John Elwes in 1881 when he visited Sikkim with Frederick DuCane Godman. It was originally described as a species in the genus "Debis".
Document 6: Mount Chown: Mount Chown is Alberta's 36th highest peak. It is named after the Reverend Samuel Dwight Chown. It is located in the northwest corner of Jasper National Park on the border with the Willmore Wilderness Park. It lies between two glaciers the Chown Glacier and the Resthaven Glacier.
Document 7: Sikkim: In 1975, the Prime Minister of Sikkim appealed to the Indian Parliament for Sikkim to become a state of India. In April of that year, the Indian Army took over the city of Gangtok and disarmed the Chogyal's palace guards. Thereafter, a referendum was held in which 97.5 per cent of voters supported abolishing the monarchy, effectively approving union with India. India is said to have stationed 20,000 -- 40,000 troops in a country of only 200,000 during the referendum. On 16 May 1975, Sikkim became the 22nd state of the Indian Union, and the monarchy was abolished. To enable the incorporation of the new state, the Indian Parliament amended the Indian Constitution. First, the 35th Amendment laid down a set of conditions that made Sikkim an ``Associate State '', a special designation not used by any other state. A month later, the 36th Amendment repealed the 35th Amendment, and made Sikkim a full state, adding its name to the First Schedule of the Constitution.
Document 8: Naja ashei: Differences from other spitting cobras were realized in the 1960s, but N. ashei was initially regarded by most merely as a brown - coloured form of the black - necked spitting cobra (N. nigricollis). Thus, N. ashei was only classified as a distinct species in 2007, by Wolfgang Wüster (Bangor University, Wales) and Donald Broadley (Biodiversity Foundation for Africa). Royjan Taylor (Director of the Bio-Ken Snake Farm in Watamu, Kenya) was instrumental in providing specimens, among them the holotype. The specific epithet honors the late James Ashe, who founded the Bio-Ken Snake Farm and was one of the first experts to suggest N. ashei was a new species.
Document 9: Ebony Wall: Ebony Wall () is a dark, nearly vertical rock wall in Antarctica, which rises about at the head of Pettus Glacier. The wall is about long and forms a part of the western escarpment of Detroit Plateau near the base of Trinity Peninsula. It was charted in 1948 by the Falkland Islands Dependencies Survey who applied the descriptive name.
Document 10: Pawan Kumar Chamling: Pawan Kumar Chamling (born 22 September 1950) is the fifth and incumbent Chief minister of the Indian state of Sikkim. Chamling is the founder president of the Sikkim Democratic Front, which has governed the state for five successive terms since 1994.
Document 11: Kathmandu: The National Museum is located in the western part of Kathmandu, near the Swayambhunath stupa in an historical building. This building was constructed in the early 19th century by General Bhimsen Thapa. It is the most important museum in the country, housing an extensive collection of weapons, art and antiquities of historic and cultural importance. The museum was established in 1928 as a collection house of war trophies and weapons, and the initial name of this museum was Chhauni Silkhana, meaning "the stone house of arms and ammunition". Given its focus, the museum contains many weapons, including locally made firearms used in wars, leather cannons from the 18th–19th century, and medieval and modern works in wood, bronze, stone and paintings.
Document 12: Sikkim (film): Sikkim is a 1971 Indian documentary about the nation of Sikkim, directed by Satyajit Ray. The documentary was commissioned by the Chogyal (King) of Sikkim at a time when he felt the sovereignty of Sikkim was under threat from both China and India. Ray's documentary is about the sovereignty of Sikkim. The film was banned by the government of India, when Sikkim merged with India in 1975. In 2000, the copyright of the film was transferred to the Art and Culture Trust of Sikkim. The ban was finally lifted by the Ministry of External Affairs (MEA) in September 2010. In November 2010 the director of the Kolkata film festival stated that upon screening the documentary for the first time, he received an injunction from the court of Sikkim again banning the film.
Document 13: Wallqani: Wallqani (Aymara "wallqa" collar, "-ni" a suffix to indicate ownership, "the one with a collar", Hispanicized spelling "Hualcani") is a mountain in the Andes of southern Peru. It is located at the border of the Moquegua Region, General Sánchez Cerro Province, Ichuña District, and the Puno Region, Puno Province, Pichacani District. It lies northeast of Jukumarini Lake and the mountains Larama Quta and Jaqhi Jaqhini. The Larama Quta River originates south of the mountain. It flows to the south.
Document 14: Eurasian tree sparrow: P. m. dilutus, described by Charles Wallace Richmond in 1856, is resident in the extreme northeast of Iran, northern Pakistan and northwest India. It also occurs further north, from Uzbekistan and Tajikistan east to China. Compared to P. m. montanus, it is paler, with sandy-brown upperparts.
Document 15: Our Films, Their Films: Our Films, Their Films is an anthology of film criticism by noted Bengali filmmaker, composer and writer Satyajit Ray. Collecting articles and personal journal excerpts, it was first published in India in 1976; an English translation was published in The United States and United Kingdom in 1992. Some of articles were previously published in the bulletin of the Calcutta Film Society which Ray co-founded in 1947.
ground_truth: Satyajit Ray
sub_queries: Chumbi Valley >> located in the administrative territorial entity Answer: Sikkim
Sikkim >> screenwriter Answer: Satyajit Ray