code: def where_equals(self, field_name, value, exact=False):
          
          if field_name is None:
              raise ValueError("None field_name is invalid")
  
          field_name = Query.escape_if_needed(field_name)
          self._add_operator_if_needed()
  
          token = "equals"
          if self.negate:
              self.negate = False
              token = "not_equals"
  
          self.last_equality = {field_name: value}
          token = _Token(field_name=field_name, value=self.add_query_parameter(value), token=token, exact=exact)
          token.write = self.rql_where_write(token)
          self._where_tokens.append(token)
  
          return self
docs: To get all the document that equal to the value in the given field_name
  
          @param str field_name: The field name in the index you want to query.
          @param value: The value will be the fields value you want to query
          @param bool exact: If True getting exact match of the query