How to use the pypika.terms.Function function in PyPika

class ToUInt64(Function):
    def __init__(self, name, alias: str = None):
        super(ToUInt64, self).__init__("toUInt64", name, alias=alias)


class ToFloat32(Function):
    def __init__(self, name, alias: str = None):
        super(ToFloat32, self).__init__("toFloat32", name, alias=alias)


class ToFloat64(Function):
    def __init__(self, name, alias: str = None):
        super(ToFloat64, self).__init__("toFloat64", name, alias=alias)


class ToDate(Function):
    def __init__(self, name, alias: str = None):
        super(ToDate, self).__init__("toDate", name, alias=alias)


class ToDateTime(Function):
    def __init__(self, name, alias: str = None):
        super(ToDateTime, self).__init__("toDateTime", name, alias=alias)

class ToUInt16(Function):
    def __init__(self, name, alias: str = None):
        super(ToUInt16, self).__init__("toUInt16", name, alias=alias)


class ToUInt32(Function):
    def __init__(self, name, alias: str = None):
        super(ToUInt32, self).__init__("toUInt32", name, alias=alias)


class ToUInt64(Function):
    def __init__(self, name, alias: str = None):
        super(ToUInt64, self).__init__("toUInt64", name, alias=alias)


class ToFloat32(Function):
    def __init__(self, name, alias: str = None):
        super(ToFloat32, self).__init__("toFloat32", name, alias=alias)


class ToFloat64(Function):
    def __init__(self, name, alias: str = None):
        super(ToFloat64, self).__init__("toFloat64", name, alias=alias)


class ToDate(Function):
    def __init__(self, name, alias: str = None):
        super(ToDate, self).__init__("toDate", name, alias=alias)


class ToDateTime(Function):
    def __init__(self, name, alias: str = None):

)


class TimeDiff(Function):
    def __init__(self, start_time, end_time, alias=None):
        super(TimeDiff, self).__init__("TIMEDIFF", start_time, end_time, alias=alias)


class DateAdd(Function):
    def __init__(self, date_part, interval, term, alias=None):
        super(DateAdd, self).__init__(
            "DATE_ADD", date_part, interval, term, alias=alias
        )


class ToDate(Function):
    def __init__(self, value, format_mask, alias=None):
        super(ToDate, self).__init__("TO_DATE", value, format_mask, alias=alias)


class Timestamp(Function):
    def __init__(self, term, alias=None):
        super(Timestamp, self).__init__("TIMESTAMP", term, alias=alias)


class TimestampAdd(Function):
    def __init__(self, date_part, interval, term, alias=None):
        super(TimestampAdd, self).__init__(
            "TIMESTAMPADD", date_part, interval, term, alias=alias
        )

class Upper(Function):
    def __init__(self, term, alias=None):
        super(Upper, self).__init__("UPPER", term, alias=alias)


class Lower(Function):
    def __init__(self, term, alias=None):
        super(Lower, self).__init__("LOWER", term, alias=alias)


class Substring(Function):
    def __init__(self, term, start, stop, alias=None):
        super(Substring, self).__init__("SUBSTRING", term, start, stop, alias=alias)


class Reverse(Function):
    def __init__(self, term, alias=None):
        super(Reverse, self).__init__("REVERSE", term, alias=alias)


class Trim(Function):
    def __init__(self, term, alias=None):
        super(Trim, self).__init__("TRIM", term, alias=alias)


class SplitPart(Function):
    def __init__(self, term, delimiter, index, alias=None):
        super(SplitPart, self).__init__(
            "SPLIT_PART", term, delimiter, index, alias=alias
        )

def get_special_params_sql(self, **kwargs):
        return "FROM {field}".format(field=self.field,)


# Null Functions
class IsNull(Function):
    def __init__(self, term, alias=None):
        super(IsNull, self).__init__("ISNULL", term, alias=alias)


class Coalesce(Function):
    def __init__(self, term, *default_values, **kwargs):
        super(Coalesce, self).__init__("COALESCE", term, *default_values, **kwargs)


class IfNull(Function):
    def __init__(self, condition, term, **kwargs):
        super(IfNull, self).__init__("IFNULL", condition, term, **kwargs)


class NVL(Function):
    def __init__(self, condition, term, alias=None):
        super(NVL, self).__init__("NVL", condition, term, alias=alias)

def __init__(self, *terms, **kwargs):
        super(Concat, self).__init__("CONCAT", *terms, **kwargs)


class Insert(Function):
    def __init__(self, term, start, stop, subterm, alias=None):
        term, start, stop, subterm = [term for term in [term, start, stop, subterm]]
        super(Insert, self).__init__("INSERT", term, start, stop, subterm, alias=alias)


class Length(Function):
    def __init__(self, term, alias=None):
        super(Length, self).__init__("LENGTH", term, alias=alias)


class Upper(Function):
    def __init__(self, term, alias=None):
        super(Upper, self).__init__("UPPER", term, alias=alias)


class Lower(Function):
    def __init__(self, term, alias=None):
        super(Lower, self).__init__("LOWER", term, alias=alias)


class Substring(Function):
    def __init__(self, term, start, stop, alias=None):
        super(Substring, self).__init__("SUBSTRING", term, start, stop, alias=alias)


class Reverse(Function):
    def __init__(self, term, alias=None):

class Lower(Function):
    def __init__(self, term, alias=None):
        super(Lower, self).__init__("LOWER", term, alias=alias)


class Substring(Function):
    def __init__(self, term, start, stop, alias=None):
        super(Substring, self).__init__("SUBSTRING", term, start, stop, alias=alias)


class Reverse(Function):
    def __init__(self, term, alias=None):
        super(Reverse, self).__init__("REVERSE", term, alias=alias)


class Trim(Function):
    def __init__(self, term, alias=None):
        super(Trim, self).__init__("TRIM", term, alias=alias)


class SplitPart(Function):
    def __init__(self, term, delimiter, index, alias=None):
        super(SplitPart, self).__init__(
            "SPLIT_PART", term, delimiter, index, alias=alias
        )


class RegexpMatches(Function):
    def __init__(self, term, pattern, modifiers=None, alias=None):
        super(RegexpMatches, self).__init__(
            "REGEXP_MATCHES", term, pattern, modifiers, alias=alias
        )

from pypika import (
    functions as fn,
    terms,
)
from pypika.dialects import SnowflakeQuery
from .base import Database

try:
    from snowflake import connector as snowflake
except:
    pass

IGNORED_SCHEMAS = {'INFORMATION_SCHEMA'}


class Trunc(terms.Function):
    """
    Wrapper for TRUNC function for truncating dates.
    """

    def __init__(self, field, date_format, alias=None):
        super(Trunc, self).__init__('TRUNC', field, date_format, alias=alias)
        # Setting the fields here means we can access the TRUNC args by name.
        self.field = field
        self.date_format = date_format
        self.alias = alias


class SnowflakeDatabase(Database):
    """
    Snowflake client.
    """

class ToChar(Function):
    def __init__(self, term, as_type, alias=None):
        super(ToChar, self).__init__("TO_CHAR", term, as_type, alias=alias)


class Signed(Cast):
    def __init__(self, term, alias=None):
        super(Signed, self).__init__(term, SqlTypes.SIGNED, alias=alias)


class Unsigned(Cast):
    def __init__(self, term, alias=None):
        super(Unsigned, self).__init__(term, SqlTypes.UNSIGNED, alias=alias)


class Date(Function):
    def __init__(self, term, alias=None):
        super(Date, self).__init__("DATE", term, alias=alias)


class DateDiff(Function):
    def __init__(self, interval, start_date, end_date, alias=None):
        super(DateDiff, self).__init__(
            "DATEDIFF", interval, start_date, end_date, alias=alias
        )


class TimeDiff(Function):
    def __init__(self, start_time, end_time, alias=None):
        super(TimeDiff, self).__init__("TIMEDIFF", start_time, end_time, alias=alias)

function_sql = "{schema}.{function}".format(
                schema=self.schema.get_sql(
                    quote_char=quote_char, dialect=dialect, **kwargs
                ),
                function=function_sql,
            )

        if with_alias:
            return format_alias_sql(
                function_sql, self.alias, quote_char=quote_char, **kwargs
            )

        return function_sql


class AggregateFunction(Function):
    is_aggregate = True


class AnalyticFunction(Function):
    is_analytic = True

    def __init__(self, name, *args, **kwargs):
        super(AnalyticFunction, self).__init__(name, *args, **kwargs)
        self._partition = []
        self._orderbys = []
        self._include_over = False

    @builder
    def over(self, *terms):
        self._include_over = True
        self._partition += terms