<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def validate(self):
 """Validate that the Variable is correctly representable."""

        # Get the first letter, or empty string if it doesn't exist.
        if not self.variable_name.startswith(u'$'):
            raise GraphQLCompilationError(u'Expected variable name to start with $, but was: '
                                          u'{}'.format(self.variable_name))

        if self.variable_name in RESERVED_MATCH_KEYWORDS:
            raise GraphQLCompilationError(u'Cannot use reserved MATCH keyword {} as variable '
                                          u'name!'.format(self.variable_name))

        validate_safe_string(self.variable_name[1:])

        if not is_graphql_type(self.inferred_type):
            raise ValueError(u'Invalid value of "inferred_type": {}'.format(self.inferred_type))

        if isinstance(self.inferred_type, GraphQLNonNull):
            raise ValueError(u'GraphQL non-null types are not supported as "inferred_type": '
                             u'{}'.format(self.inferred_type))

        if isinstance(self.inferred_type, GraphQLList):
            inner_type = strip_non_null_from_type(self.inferred_type.of_type)
            if GraphQLDate.is_same_type(inner_type) or GraphQLDateTime.is_same_type(inner_type):
                # This is a compilation error rather than a ValueError as
                # it can be caused by an invalid GraphQL query on an otherwise valid schema.
                # In other words, it's an error in writing the GraphQL query, rather than
                # a programming error within the library.
                raise GraphQLCompilationError(
                    u'Lists of Date or DateTime cannot currently be represented as '
                    u'Variable objects: {}'.format(self.inferred_type))