Question: In what country is the county where Tyesha Mattis was born?

full_context: Document 1: All-Hallows-the-Great: All-Hallows-the-Great was a church in the City of London, located on what is now Upper Thames Street, first mentioned in 1235. Destroyed in the Great Fire of London of 1666, the church was rebuilt by the office of Sir Christopher Wren. All-Hallows-the-Great was demolished in 1894 when many bodies were disinterred from the churchyard and reburied at Brookwood Cemetery.
Document 2: Hackney Empire: The Hackney Empire is a theatre on Mare Street, in the London Borough of Hackney, built in 1901 as a music hall.
Document 3: Giles Matthey: Giles Matthey was born in Australia to a British father and an Australian mother. He moved to London with his family at the age of 2. He has one sibling, a younger sister Arabella, who is a Security Consultant. He became interested in acting during his teenage years and eventually moved to New York City. In the US, he completed a two-year conservatory program at the Lee Strasberg Theatre and Film Institute.
Document 4: Hackney, Guyana: Hackney, is a village in Guyana, standing on the eastern bank of the Pomeroon River, 11 km from its mouth. Formerly the business centre for residents of the coconut estates of the lower Pomeroon River, Hackney is still of some importance. It provides a primary school and church for residents of the surrounding area.
Document 5: Natasha Kaiser-Brown: Kaiser-Brown was born in Des Moines, Iowa. In high school, she was a nine-time state champion for Des Moines Roosevelt and is the previous record-holder for the 100 meter and sprint medley relay events (both broken in the 2018 track season).
Document 6: St Anne and St Agnes: St Anne and St Agnes was rebuilt by Sir Christopher Wren in 1680, with possible contributions from Robert Hooke. The small brick church is of an unusual design in London, being based on that of a Greek cross; it utilises a vaulted square within a square, a formula based on the Nieuwe Kerk in Haarlem in the Netherlands. Wren also used a similar design at St Martin Ludgate and St Mary-at-Hill. The parish was united with the parish of St John Zachary by Act of Parliament in 1670 as St John's was not rebuilt after the Great Fire.
Document 7: Jess Glynne: Jess Glynne was born in Hampstead and raised in Muswell Hill, North London, in a Jewish family. Her father, Laurence Glynne, is an estate agent; and her mother, Alexandra (née Ingram), worked in A&R in the music industry. The family name was originally Goldstein, but her grandfather changed it to Glynne. She applied for the television show "The X Factor" when she was 15 years old, but dropped out of the audition process following a disagreement with the producers. She attended Rhodes Avenue Primary School, then attended Fortismere School, where she completed her A-levels in 2008, and took various jobs at a boutique, a fitness centre and a hairdresser's. After a period spent travelling the world, Glynne worked for a music management company in her late teens and began networking with songwriters and producers, eventually honing her artistry for four years.
Document 8: Cape plc: Cape plc is a United Kingdom energy services company based in West Drayton, Middlesex. It was acquired by Altrad in September 2017.
Document 9: Ambit Energy: Ambit Energy is an International multi-level marketing company that provides electricity and natural gas services in energy markets in the U.S. that have been deregulated.The company's corporate headquarters are located in Dallas, Texas, and its operations/call center headquarters are located in Plano, Texas. Ambit Energy was founded in 2006 in Addison, Texas by Jere Thompson Jr. and Chris Chambless.
Document 10: Capita: Capita was formed 1984 as a division of the non-profit CIPFA (Chartered Institute of Public Finance and Accountancy). In 1987 it became an independent company with 33 staff as a result of a management buy - out, led by Rod Aldridge, and was first listed on the London Stock Exchange in 1991.
Document 11: Hackney (parish): Hackney was a parish in the historic county of Middlesex. The parish church of St John-at-Hackney was built in 1789, replacing the nearby former 16th-century parish church dedicated to St Augustine (pulled down in 1798). The original tower of that church was retained to hold the bells until the new church could be strengthened; the bells were finally removed to the new St John's in 1854. See details of other, more modern, churches within the original parish boundaries below.
Document 12: Capita: It is the largest business process outsourcing and professional services company in the UK, with an overall market share of 29% in 2016, and has clients in central government, local government and the private sector. It also has a property and infrastructure consultancy division which is the fourth largest multidisciplinary consultancy in the UK. Roughly half of its turnover comes from the private sector and half from the public sector. Whilst UK-focused, Capita also has operations across Europe, Africa and Asia.
Document 13: Yasemin Dalkılıç: Yasemin Dalkılıç was born and grew up in Ankara, Turkey, some away from the nearest coast. At age 14, she was a member of the national monofin finswimming team, where she stayed for several years and set several Turkish records. By the time she was 16, she had established herself as the best freediver in her country. In 1996, she started as a student in the mathematics department at the Middle East Technical University in Ankara, where she became a member of the Subaqua Society.
Document 14: Cascade AIDS Project: Cascade AIDS Project (CAP) is a nonprofit organization based in Portland, Oregon, in the United States. Its mission is to prevent HIV infections, to "support and empower" people affected and by HIV/AIDS, and to eliminate stigma associated with the disease. Founded in 1983 and incorporated two years later, CAP is the "oldest and largest community-based provider of HIV services, housing, education and advocacy" in Oregon and Southwest Washington.
Document 15: Tyesha Mattis: Tyesha Mattis (born 17 April 1999 in Hackney, London) is a British artistic gymnast. She trains at City Of London Gymnastics Club
ground_truth: United Kingdom
sub_queries: Tyesha Mattis >> place of birth Answer: Hackney
Hackney >> located in the administrative territorial entity Answer: Middlesex
Middlesex >> country Answer: United Kingdom