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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 find_declaration( declarations, decl_type=None, name=None, parent=None, recursive=True, fullname=None):
 """ Returns single declaration that match criteria, defined by developer. If more the one declaration was found None will be returned. For more information about arguments see :class:`match_declaration_t` class. :rtype: matched declaration :class:`declaration_t` or None """


    decl = find_all_declarations(
        declarations,
        decl_type=decl_type,
        name=name,
        parent=parent,
        recursive=recursive,
        fullname=fullname)
    if len(decl) == 1:
        return decl[0]