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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def emit_code_from_multiple_match_queries(match_queries):
 """Return a MATCH query string from a list of MatchQuery namedtuples."""

    optional_variable_base_name = '$optional__'
    union_variable_name = '$result'
    query_data = deque([u'SELECT EXPAND(', union_variable_name, u')', u' LET '])

    optional_variables = []
    sub_queries = [emit_code_from_single_match_query(match_query)
                   for match_query in match_queries]
    for (i, sub_query) in enumerate(sub_queries):
        variable_name = optional_variable_base_name + str(i)
        variable_assignment = variable_name + u' = ('
        sub_query_end = u'),'
        query_data.append(variable_assignment)
        query_data.append(sub_query)
        query_data.append(sub_query_end)
        optional_variables.append(variable_name)

    query_data.append(union_variable_name)
    query_data.append(u' = UNIONALL(')
    query_data.append(u', '.join(optional_variables))
    query_data.append(u')')

    return u' '.join(query_data)