A Set is a data structure that allows only one occurrence of a value to be stored in it at any one time. An attempt to insert a second copy of a value is rejected. Note that data is not stored in any particular order in the Set. Define the following methods for an array-based Set. class Set: def __init__(self): """ ------------------------------------------------------- Initializes an empty Set. Use: s = Set() ------------------------------------------------------- Returns: Initializes an empty set. ------------------------------------------------------- """ # your code here return def is_empty(self): """ ------------------------------------------------------- Determines if the set is empty. Use: b = s.is_empty() ------------------------------------------------------- Returns: True if the set is empty, False otherwise. ------------------------------------------------------- """ return len(self._values) == 0 def __len__(self): """ ------------------------------------------------------- Returns the size of the set. Use: n = len(s) ------------------------------------------------------- Returns: the number of values in the set. ------------------------------------------------------- """ return len(self._values) def _linear_search(self, key): """ ------------------------------------------------------- Searches for the first occurrence of key in the set. Private helper method - used only by other ADT methods. Use: i = self._linear_search(key) ------------------------------------------------------- Parameters: key - a partial data element (?) Returns: i - the index of key in the set, -1 if key is not found (int) ------------------------------------------------------- """ # your code here return i def insert(self, i, value): """ ------------------------------------------------------- Inserts value at the proper place in the set. Use: b = s.insert(i, value) ------------------------------------------------------- Parameters: i - index value (int) value - a data element (?) Returns: inserted - True if the value was inserted at i, False otherwise. value is inserted at position i or appended to the end of the set if i > len(s) only if value is unique in the set (boolean) ------------------------------------------------------- """ # your code here return def remove(self, key): """ ------------------------------------------------------- Finds, removes, and returns the value in the set that matches key. Use: value = s.remove( key ) ------------------------------------------------------- Parameters: key - a partial data element (?) Returns: value - the full value matching key, otherwise None (?) ------------------------------------------------------- """ # your code here return value def find(self, key): """ ------------------------------------------------------- Finds and returns a copy of value in the set that matches key. Use: value = s.find( key ) ------------------------------------------------------- Parameters: key - a partial data element (?) Returns: value - a copy of the full value matching key, otherwise None (?) ------------------------------------------------------- """ assert len(self._values) > 0, "Cannot find in an empty set" # your code here return value def peek(self): """ ------------------------------------------------------- Returns a copy of the first value in list. Use: value = s.peek() ------------------------------------------------------- Returns: value - a copy of the first value in the set (?) ------------------------------------------------------- """ assert len(self._values) > 0, "Cannot peek at an empty set" # your code here return value def index(self, key): """ ------------------------------------------------------- Finds the location of the first occurrence of key in the set. Use: n = s.index( key ) ------------------------------------------------------- Parameters: key - a data element (?) Returns: i - the location of the full value matching key, otherwise -1 (int) ------------------------------------------------------- """ # your code here return i def _valid_index(self, i): """ ------------------------------------------------------- Private helper method to validate an index value. Python index values can be positive or negative and range from -len(set) to len(set) - 1 Use: assert self._valid_index(i) ------------------------------------------------------- Parameters: i - an index value (int) Returns: True if i is a valid index, False otherwise. ------------------------------------------------------- """ n = len(self._values) return -n <= i < n